Preheat your oven to 425°F. Season salmon lightly with salt, pepper, and a touch of garlic powder. Place on a baking sheet and bake for 20 minutes until the flesh flakes easily with a fork. Once done, increase oven temperature to 450°F.
While salmon cools slightly, flake it into bite-sized pieces and remove any skin. In a mixing bowl, combine flaked salmon, cream cheese, 1/2 cup Japanese mayo, and sriracha. Mix until well combined but leave some bigger chunks of salmon for texture.
In a small bowl, mix together rice vinegar, sugar, and salt. Gently fold this mixture into your cooked rice until evenly distributed. Don't mash the rice.
In a 9x13 inch casserole dish, spread the seasoned rice evenly across the bottom and press down gently to create a compact foundation.
Sprinkle a generous amount of furikake over the rice layer.
Spread the creamy salmon mixture over the furikake layer using a spatula, getting it to all the edges.
Drizzle Japanese mayo, sriracha, and eel sauce over the top in a zigzag pattern. Finish with another sprinkle of furikake on top.
Bake at 450°F for 10 minutes. Then switch to broil for 3 minutes, watching carefully. You want golden and slightly crispy, not burnt.
Remove from oven and immediately sprinkle sliced green onions over the top. Let cool for a few minutes before serving.
Serve warm with roasted seaweed sheets, sliced cucumbers, avocado, and extra sauces on the side. Scoop into nori sheets like a taco or eat directly from the dish.