Step 1

Rinse rice and drain. Add rice to a pot and pour in water. Bring to a simmer over high heat, then reduce heat to low. Cover and cook for 20 minutes. Turn off heat and let rest for 10 minutes.

Step 2

While rice cooks, combine rice vinegar, sugar, and salt together in a small bowl until dissolved. Set aside.

Step 3

Preheat the oven to 400 degrees F (200 degrees C). Lightly grease a shallow 2-quart baking dish with some sesame oil.

Step 4

Uncover rice and drizzle over seasoned vinegar mixture. Use a fork to break up and fluff rice. Transfer rice into the prepared baking dish. Sprinkle over toasted sesame seeds, bonito flakes, and nori; use a fork to gently stir into the rice.

Step 5

Mix mayonnaise, soy sauce, ½ teaspoon sesame oil, and Sriracha for topping together in a bowl and stir in scallops and shrimp. Spread over rice, and sprinkle cayenne over the top.

Step 6

Bake in the center of the preheated oven until the seafood is just cooked through (or 95% cooked through), about 20 minutes. Turn oven to a high broil setting, and brown the top, 1 to 2 minutes. Garnish the top with more Sriracha, toasted sesame seeds, and green onions before serving.