Let’s Make Tuna Onigiri (Rice Ball)

Every time we visit Japan, we would eat rice balls or onigiri whenever we want a light meal or snack. That’s because they are delicious and convenient! While you can find onigiri in every convenient store, the best tasting rice balls I found were from specialty shops where rice is pretty much the only thing you can buy, such as rice balls or rice cooked with other ingredients. These places often have onigiri made with seasonal ingredients and I find the texture of their rice balls more superior (likely because they are made fresh).

Making Tuna Onigiri at home

At home, I like to make onigiri for picnics or simple lunch/snack. You can basically fill the inside of the rice ball with whatever you fancy. Here I used canned tuna because it’s readily available. But chopped up cooked chicken, beef, seafood, tofu, or veggies will also work.

For the onigiri, I use short grain rice. Short grain or Japanese rice is slightly sticky so the onigiri stays together better. A bit like sticky rice but not as much as glutenous rice. Also, I find that it’s best to fluff up the rice right after it’s cooked. Then cover and let it rest in the rice cooker for 10 minutes or so. Fluff it up again before making the onigiri. Rice that just finished cooking tends to be too moist. The resting allows it to absorb most of the moisture, giving the rice ball a firmer and drier texture.

Shaping Onigiri by Hand or Mold

Tuna Onigiri Rice Ball Recipe - Shaping Onigiri by hand

I don’t have an onigiri mold so I shape my rice ball by hand. Here are some basics if you want to shape onigiri by hand. Start by putting your hands in a bowl of water to moisten them. Then sprinkle some sea salt on your hands. The water will prevent the rice from sticking to your hands and the salt will help season the as you shape the rice ball. Put about 1/2 to 3/4 cup of rice in your palm, make a dent in the middle, and place your filling there. Now place about 2 table spoons of rice on top of the filling and enclose the sides by pushing the rice towards of your palms with both hands. Watch this video on how to shape onigiri into a triangle.

If you have an onigiri mold, simply fill the mold 1/2 way with rice. Add your filling then top the mold with rice. Press the two pieces of the mold together and you’ll have perfectly shaped rice ball every time.

Easiest Way to Shape Onigiri

Since you need to work with hot rice, I find the easiest way to handle to make the rice ball is to use plastic wrap. Simply use a large piece of plastic wrap, place your rice on top, then gather up the sides of the plastic wrap to bring the rice together. Now you can form your onigiri into the desired shape without rice sticking to your hands.

Tuna Onigiri (Rice Ball) Recipe

Onigiri makes for a convenient snacks or light meal, especially if you're on the run. Fill the rice balls with anything you fancy, then bring these for picnics, pack them for lunches or simply munch on them as an afternoon snack.
Course: Snack
Cuisine: Japanese
Keyword: onigiri, rice
Servings: 4 pieces
Author: Jan Chan


  • 3 cups fresh, cooked rice (hot or still warm to the touch)
  • 1 can tuna, drained (I use low sodium, solid tuna packed in water)
  • 3 tbsp mayo (add more if you want a creamier consistency)
  • Sriracha or Tabasco sauce (optional)
  • sea salt & fresh ground pepper, to taste
  • toasted nori or seaweed (optional)


  • Put the tuna in a bowl and flake it into smaller pieces with a fork. Mix in mayo and season with salt and pepper. Add in some sriracha or Tabasco sauce if you want a bit of heat.
  • Use the rice paddle to loosen up the rice and season it with a bit of salt (to your preference). Divide the rice up into 4 equal portions.
  • Take a piece of plastic wrap that's large enough to wrap around one portion of rice and lay it on your palm. Curl your fingers so your palm forms a shallow cup shape and scoop a portion of rice on top of the plastic wrap. Spread the rice out so it covers most of your palm with an indent in the middle. Then add a spoonful or two of the tuna filling.  Pull the edges of the plastic wrap up so the rice encloses the tuna filling and forms a rough circle.
  • For a round rice ball: Rolling the rice ball between the palms of your hands to form a circular shape.
  • For a triangular rice ball: Cup the rice ball between your hands and rotate the rice ball while pressing towards it with your fingers and the heel of your palm. Watch the video mentioned above which will give you a better idea on how to shape a rice ball into a triangle. 
  • Remove the plastic wrap and your first rice ball is ready! Repeat with the remaining portion of rice. If you like, wrap a piece of toasted nori (seaweed) around the onigiri.

How to Make Tuna Onigiri Recipe

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