Begin by cooking the uncooked sushi rice according to the package instructions, which typically takes about 20 minutes. Mix rice vinegar and sugar in a microwave-safe bowl until dissolved, then gently fold into warm rice and set aside.

Preheat your oven to 400℉ (200℃). In a bowl, combine cubed fresh salmon with light soy sauce, Kewpie mayo, sriracha, and sesame oil. Mix well until the salmon is coated.

Cut nori sheets into squares that fit into muffin tin cups, leaving a little overhang to create crispy edges.

Grease muffin tin lightly. Press a small amount of sushi rice into the bottom of each nori square and layer salmon mixture generously on top.

Bake for about 15 minutes or until the salmon is cooked through and the tops are golden. Keep an eye on them as they bake.

Remove from oven, let cool for a few minutes, drizzle with spicy mayo, sprinkle furikake, and garnish with chopped green onions before serving warm.