Rinse 2 cups of sushi rice under cold water until the water runs clear. Combine with 2.5 cups of water in a medium pot and bring to a boil. Cover, reduce heat to low, and simmer for 18-20 minutes. Let sit covered for 10 minutes.

Transfer cooled sushi rice to a bowl and gently fold in 1/4 cup rice vinegar, 2 tablespoons sugar, and 1 teaspoon salt. Mix without smashing the rice.

In a mixing bowl, combine 2 cups of flaked cooked salmon, 1/4 cup Kewpie mayonnaise, 2 tablespoons sriracha, 1 tablespoon soy sauce, and 1 teaspoon sesame oil. Stir until uniform.

Preheat oven to 375°F (190°C). Spread the seasoned sushi rice in a greased baking dish; pour the salmon mixture over the rice. Bake for 15-20 minutes until the top is bubbly.

Let cool for 5 minutes before topping with avocado, cucumber, nori strips, and sesame seeds. Cut into squares and serve warm.