Prepare the Rice: Rinse sushi rice thoroughly. Cook with water until done. Mix in rice vinegar and let cool.
Bake the Salmon: Season salmon with salt, pepper, and garlic powder. Bake at 400°F for 15–20 minutes. Cool and shred.
Mix the Filling: In a bowl, combine shredded salmon, crab, mayo, cream cheese, sriracha, and soy sauce. Mix until creamy.
Assemble: Spread rice in a greased 9×13 inch baking dish. Sprinkle furikake over rice. Spread seafood mixture evenly on top.
Bake and Finish: Broil for 3–4 minutes until the top begins to brown. Drizzle with spicy mayo, garnish with green onions and sesame seeds.
Serve: Scoop with roasted seaweed or cucumber slices.