* Cook the rice according to package instructions.
* Once cooked, mix in rice vinegar and let it cool slightly.
* Cut nori sheets into squares and line each muffin tin cavity with a piece of nori.
* Add a scoop of rice into each nori-lined cup and gently press down to shape.
* Bake the rice cups in a 300°F oven for about 5 minutes to help them hold their shape.
* In a bowl, combine tuna, mayonnaise, sriracha, and a pinch of salt. Mix until well combined.
* Top each rice cup with a spoonful of the tuna mixture.
* Sprinkle sesame seeds over the tuna.
* Garnish with sliced avocado and chopped green onions.
Serve and enjoy!