Preheat the oven to 350º F
In a large bowl combine crab, kewpie mayo, cream cheese, sriracha, and yum yum sauce. Set aside.
In a separate bowl, add rice, rice vinegar, mirin, and sesame oil. Stir to combine.
In a 9x13 baking dish, spread the cooked rice in an even layer.
Next, spread the crab mixture. (Use a spoon/spatula to smooth into an even layer).
Drizzle Kewpie Mayo and Sriracha over the crab mix.
Bake for 12-15 minutes.
Serve immediately with pieces of nori.