Preheat the oven to 425 degrees Fahrenheit. Line a 7 x 11'' casserole dish with parchment paper.
Rinse the rice thoroughly on a sieve under cold water.
Cook rice in water according to package instructions. I cooked mine in 1 ⅓ cups water for 20 minutes.
Let the rice cool for 10 minutes, then season with rice vinegar, salt and sugar. Mix with a rubber spatula.
While the rice is cooling, prepare the salmon topping. Dice the raw salmon and imitation crab into small pieces. Transfer to a medium bowl and mix together with mayo, sriracha and soy sauce.
Transfer the seasoned rice into the prepared casserole dish and press down into a single layer.
Sprinkle evenly with furikake.
Top with the salmon mixture and spread evenly pressing lightly.
Bake in preheated oven for 17-20 minutes.
Let cool for a few minutes, then sprinkle with chopped scallions and cut into squares.
Serve on its own with a fork or wrapped in roasted seaweed with avocado slices and spicy sriracha mayo, if desired (mix together mayo, sriracha and soy sauce until smooth).