Step 1
Preheat broiler to high. In a small saucepan bring the teriyaki sauce to a boil. Whisk the cornstarch together with 1 tablespoon water in a small bowl and whisk into the teriyaki sauce. Cook until thickened, another minute or so, and transfer the sauce to a bowl.
Step 2
Line a large sheet pan with foil. Place the fish on the pan and season with salt and pepper. Brush with thickened sauce. Broil, watching carefully and moving the sheet pan around to cook evenly, until fish is browned and cooked, about 2-4 minutes.
Step 3
To serve, flake sole into bite-sized pieces and serve with the rice, cucumbers, carrots, avocados, sprouts, remaining teriyaki sauce and wasabi paste. To build hand rolls, top the seaweed with rice, some fish, cucumbers, carrots, avocados, sprouts, wasabi, and additional teriyaki, if desired. Wrap and eat.
