Rehydrate seaweed in water for 5-10 minutes.
Cut the tuna into 1 inch cubes. Toss with soy sauce, sesame oil, seaweed, and scallions. Set in fridge for 30 minutes to chill. In the meantime, mix mayonnaise with sriracha.
Coat half of marinaded tuna in spicy mayo.
Combine all seaweed salad ingredients.
Put together the bowls starting with 1/2 - 1 cup good quality sushi rice. Top with sesame soy tuna and spicy mayo tuna, carrots, cucumber, pickled ginger and a dollop of wasabi. Sprinkle with sesame seeds and scallions.