Rinse the sushi rice under cold water until the water runs clear. In a rice cooker or saucepan, combine the rice with water and cook until tender, about 20 minutes. Let the rice rest covered for 10 minutes to steam.

In a small bowl, whisk together the rice vinegar, sugar, and salt until dissolved. Fold this mixture into the cooked sushi rice to enhance flavor.

Preheat your oven to 375°F (190°C). Grease a 9x13 inch baking dish. Spoon the seasoned rice into the dish and spread it evenly, pressing down gently.

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

Spread the salmon mixture evenly on top of the rice layer in the baking dish.

Bake in the oven for about 25-30 minutes until the salmon is cooked and the top is golden and bubbling.

Allow to cool slightly, then garnish with green onions, nori strips, and optional tobiko. Serve warm.