Rinse sushi rice under cold water until clear. Combine rice with water in rice cooker or pot, bring to boil, then simmer covered for 18-20 minutes. Let sit for 10 minutes.

Whisk together rice vinegar, sugar, and salt in a small bowl until sugar dissolves. Set aside.

Fluff cooked sushi rice with a fork. Pour vinegar mixture over rice and fold in gently. Spread rice evenly in baking dish and cool slightly.

In a mixing bowl, combine diced salmon, mayonnaise, sriracha, sesame oil, and green onions. Stir until well incorporated.

Spread salmon mixture evenly over sushi rice. Preheat oven to 375°F (190°C) and bake for 25-30 minutes until topping is golden brown.

Cool for a few minutes, garnish with additional green onions and nori, and serve warm with pickled ginger and soy sauce.