Rinse the sushi rice under cold water until the water runs clear.

In a medium saucepan, combine the rinsed rice and water. Bring to a boil, then reduce to low heat and cover, cooking for about 18 minutes.

While the rice cooks, mix the diced tuna, soy sauce, sesame oil, rice vinegar, and sriracha in a bowl.

Once the rice is cooked, let it sit covered for a few minutes, then fluff it with a fork.

Using wet hands, take a portion of rice and form it into small rectangular cakes.

Heat vegetable oil in a frying pan over medium heat. Once hot, carefully add the rice cakes and fry until golden brown on each side, about 2-3 minutes.

Once crispy, place the rice cakes on a plate and top each with the marinated tuna mixture.

Sprinkle with chopped green onions and sesame seeds. Serve immediately.