Rinse the sushi rice under cold water until the water runs clear to remove excess starch. In a rice cooker or pot, combine the rinsed rice with water according to the manufacturer's instructions and cook until tender. Once cooked, let the rice rest covered for 10 minutes to enhance its texture for the Spicy Salmon Sushi Bake.

In a small bowl, mix together rice vinegar, sugar, and salt until dissolved. Gently fold this mixture into the rested sushi rice with a wooden spatula to avoid breaking the grains.

In a separate mixing bowl, dice your fresh salmon fillet and add mayonnaise, sriracha sauce, sesame oil, and a portion of chopped green onions. Stir well until all ingredients are fully combined.

Take a baking dish and evenly spread the flavored sushi rice across the bottom, pressing it down gently to create a base. Layer the salmon mixture evenly over the rice.

Preheat your oven to 375°F (190°C). Place the assembled dish in the oven and bake for 25-30 minutes until the salmon is cooked through and the top is golden brown.

After baking, let the Spicy Salmon Sushi Bake cool slightly for about 5 minutes. Garnish with additional chopped green onions, nori strips, and tobiko if desired. Serve warm with pickled ginger and soy sauce.