Rinse the sushi rice under cold water until the water runs clear. Combine the rinsed rice with water in a rice cooker, and cook according to the machine's instructions. Let it steam for an additional 10 minutes once done.

Preheat your oven to 425°F (220°C).

Cube the salmon filet into bite-sized pieces, and mix it in a bowl with Kewpie mayo, cream cheese, sriracha, soy sauce, and chopped green onions. Stir until well-combined and creamy. Cover and refrigerate.

In a small saucepan, combine soy sauce, mirin, sake, and sugar. Simmer over medium heat for about 5 minutes until slightly thickened. Remove from heat and let cool.

In a separate bowl, whisk together mayonnaise, sriracha, lime juice, and a pinch of salt. Adjust sriracha according to taste and chill.

Grease a 9x13 baking dish with oil. Spread the cooked sushi rice evenly across the bottom, pressing down gently. Layer the chilled salmon mixture over the rice.

Place the dish in the preheated oven and bake for 10-15 minutes until the salmon is cooked through and the top is golden brown. Broil for an additional 2-3 minutes for extra crispiness.

Drizzle the unagi sauce and spicy mayo over the top. Garnish with fresh avocado slices, diced cucumber, sesame seeds, and additional green onions.

Serve the bake alongside sheets of nori, allowing everyone to wrap bites.