Tuna Onigiri Triangle Rice

This is an easy Tuna Onigiri (omusubi) recipe. My family and kids love this seaweed triangle rice. No mayo, not spicy, and delicious for kids.

Tuna Onigiri is a Favorite Recipe

My family loves eating this delicious and simple to make Tuna Onigiri. Onigiri, also known as omusubi, is affectionately called triangle rice in our home. The kids come running when I tell them I'm making triangle rice.

Why My Tuna Onigiri Recipe is Perfect For Families and Kids

To be clear, this recipe isn't an onigiri you would find in a traditional Japanese restaurant.

Instead, it's influenced by how my parents used to make me Taiwanese fan tuan when growing up. Plus, I designed this recipe with ingredients I easily buy in the US.

When I make this Tuna Onigiri, I completely mix the tuna and seasoning together with the rice. This way, the kids get a bit of tuna with every bite, as opposed to finding a wad of tuna in the middle of the triangle rice.

There is no mayo in this tuna onigiri. This recipe is not spicy. Instead the flavors from furikake and tuna stand out. Simple and delicious.

Ingredients for Tuna Onigiri

• Sweet rice
• Medium grain rice
• Furikake (the kids favorite on Amazon)
• Canned tuna (we buy this brand because every can is tested for mercury)
• Seaweed wrappers

What Type of Rice for Onigiri

I've tried many different rice combinations when making tuna onigiri. Using a combination of brown medium grain rice, white medium grain rice and sweet rice works the best for us.

Traditionally, only sweet rice is used to make rice balls. Sweet rice holds together well, so it's easy to form the triangles.

The kids and I prefer a mix of sweet rice and medium grain rice though. While it makes the triangle rice less sticky, we like the taste and texture better.

In addition, I like adding a bit of brown rice so the onigiri is a little healthier. The brown rice also adds a nutty taste that complements the sesame seed in the furikake and roasted seaweed.

What Kind of Furikake is Best for Onigiri

You can use any flavor furikake for onigiri. Every brand and variety will have slightly different tastes though. In the end, it comes down to a matter of preference.

Personally, we all like this Nori Komi Furikake best. It contains black sesame, white sesame, sugar, salt and dried black seaweed.

Trader Joe's also carries a delicious furikake that I often use for triangle rice. Both the Mishima and Trader Joe's brand use a simple flavor profile.

What Seaweed Wrapper To Use for Tuna Onigiri?

I wish I could link you to the seaweed wrappers that I used in the photos. The kids grandparents buy these seaweed wrappers in Taiwan for us and I can't find them in the US.

However, you can buy similar ones on Amazon. While the seaweed wrap functions the same, unfortunately they don't have the super cute designs like in the photos. Amazon does sell cute Minion seaweed wraps though.

How to Make Tuna Onigiri

The full recipe and directions are below. It's a very easy that only takes a few steps. Here's a quick summary:

1. Cook the rice
2. Mix the rice, tuna, and furikake together
3. Shape the rice using triangle molds
4. Wrap the triangle rice in seaweed wrappers

How to Shape the Rice Into Triangles

We love using these rice molds to make triangle shapes. By using the mold, it's easy to make consistent sized triangles that are firmly held together.

This is the onigiri mold that we use at home. There are different types available, but I love this style. There is a bottom container and a top piece that is used to push the triangle rice firmly together.

It is not necessary to grease or prep the triangle molds before adding the rice, but dipping it in a bowl of water is helpful. It also helps to use slightly wet hands to prevent the rice from sticking.

How Can Kids Help Make Onigiri

There are so many steps that the kids can do to help make Tuna Onigiri. My kids love making this together. Kids can:

• Sprinkle the furikake into the bowl of rice
• Add the tuna into the bowl of rice
• Mix the rice and toppings together
• Fill the triangle molds with rice
• Push down the top of the triangle mold to compress the rice
• Transfer the compressed triangle rice onto the seaweed strip
• Place the sticker to close the wrapped onigiri

I only need to do a few simple steps when supervising the kids: cook the rice, open the can of tuna, hold the seaweed wrappers around the triangle rice for them to put the sticker on.

How Many Seaweed Triangle Rice Per Kid

My 8-year-old eats two of these when he's hungry, and my 4-year-old just about polishes off one.

We serve these Tuna Onigiri with some cucumber slices or edamame.

Can I Make Tuna Onigiri with Leftover Rice?

Tuna Onigiri tastes best when made with freshly cooked rice. However, it is possible to make triangle rice with leftover rice.

Often, I will cook the full amount of rice in the recipe below. But, I will make three triangle rice on the first day, then another three the next day.

Save leftover rice in an airtight container in the fridge. When you are ready to make onigiri with leftover rice, take these few extra steps when reheating the rice.

• Sprinkle some water over the cold rice
• Cover the rice with a wet paper towel before reheating in the microwave
• Make sure the rice is completely heated through to fully soften it

While Tuna Onigiri made with leftover rice doesn't hold together as securely, it does hold together well enough to enjoy.

Print

5 from 1 vote

Tuna Onigiri

This is an easy Tuna Onigiri (omusubi) recipe. My family and kids love this seaweed triangle rice. No mayo, not spicy, and delicious for kids.

Prep Time1 hour hr 10 minutes mins

Active Time25 minutes mins

Course: Main Course

Prep Time: 1 hour hour 10 minutes minutes

Cook Time: 25 minutes minutes

Yield: 6 Onigiri

Ingredients

• 1 cup uncooked medium grain rice white, brown, or a mix (see notes)
• 1 ¼ cups uncooked short grain sweet rice (see notes)
• 1 5-oz can tuna
• furikake to taste

Instructions

• Mix the rice together. Rinse the rice with water a couple of times. Cook the rice in a rice cooker, Instant Pot, or your choice of cooking vessel. I usually cook rice for this recipe in an Instant Pot and use a 1:1 ratio of rice and water.
• When the rice is done cooking, allow it to cool slightly. In a large bowl (or the pot the rice cooked in) add in the tuna and furikake. Gently, use a rice spatula to fold the rice to mix. Try to use a slice, lift and fold motion, as opposed to stirring motion.
• When the rice is mixed enough, fill the triangle mold with rice. The rice should slightly overfill the mold. Cover with the lid and push down firmly. You should feel resistance when the rice compresses. If the rice compresses too easily, add some more rice and push down with the lid again. If the rice is not compressed enough, the triangle will fall apart when you eat it.
• Get a sheet of seaweed ready. Remove the lid and flip the mold over so the triangle rice is correctly positioned on the seaweed. Follow the instructions on the seaweed package for folding and closing the wrapper.
• Serve and enjoy warm or at room temperature.

Notes

The total amount of rice in this recipe is 2 ¼ US cup, which is equivalent to 3 full rice measuring cups. If using a rice measuring cup, use ½ medium grain rice and ½ sweet rice. 

Ideally, do not use more brown medium grain rice than white medium grain rice. Also do not use more medium grain rice than sweet rice. The triangle rice will not hold its shape well if you use too much brown rice, or not enough sweet rice. 

Any questions? Feel free to ask in the comments below. I really hope this delicious Tuna Onigiri makes it on to your family table soon.

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