Preheat your oven to 400°F.
Steam the cauliflower rice until tender, then mix it with the cooked white rice and rice vinegar in a bowl.
Remove the skin from the salmon and chop both the salmon and peeled shrimp into small, bite-sized pieces.
In a separate bowl, combine the chopped seafood with Greek yogurt, sriracha, coconut aminos, sea salt, and garlic powder until well coated.
Press the rice and cauliflower mixture firmly into the bottom of a small individual-sized baking dish.
Spread the seafood mixture evenly over the top of the rice layer.
Bake for 12 to 15 minutes until the salmon is opaque and the shrimp is pink and cooked through.
While baking, dice the cucumber and avocado and shred the nori sheet into thin strips.
Remove the dish from the oven and top with the fresh cucumber, avocado, and nori strips before serving warm.