Preheat your oven to 400F and prepare a 6-inch baking pan.
In a bowl, add in your rice and heat it in the microwave for 1 minute. This is so it's easier for the sugar and rice vinegar to soak in. Add in your rice vinegar and sugar and mix well.
Next, add in the rice mixture to your baking pan in an even layer. Sprinkle furikake on top.
Use the same bowl that you mixed up your rice in and add in your drained canned tuna, sesame oil, sriracha, and mayo and mix well.
Add the layer of saucy tuna on your rice layer evenly on top. Sprinkle with furikake.
Bake at 400F for 20-30 minutes or until the top is golden brown.
Serve with a side of seasoned seaweed and enjoy!