Begin by removing the skin from the salmon fillet and cutting it into 1-inch cubes. In a mixing bowl, combine the salmon with teriyaki sauce and kosher salt, ensuring that each piece is well-coated. Allow the salmon to marinate for about 15 minutes while you prep the rest of the dish.

Preheat your oven to 400°F (200°C) while you prepare a small baking dish. Firmly press the cooked sushi rice into the bottom of the dish, creating an even layer. Next, evenly distribute the marinated salmon mixture over the rice.

Sprinkle garlic powder and brown sugar on top to enhance the flavors and add a hint of sweetness.

Once the oven is preheated, switch to the broiler setting and place the baking dish on the middle rack. Broil for approximately 6 minutes, watching closely.

Carefully remove the baking dish from the oven and let it cool slightly. While it's still warm, top the dish with freshly cubed avocado, a drizzle of spicy mayo, and a sprinkle of furikake.

Finish off with crispy fried onion bits and sliced scallions for added crunch and garnish. Serve hot straight from the oven.