Salmon and Shrimp Nigiri
For the salmon sushi, cut the well-chilled salmon fillets diagonally into 8 very thin and uniform slices, about 3 x 5 cm (approximately 1 x 2 inches), then spread a thin coating of wasabi paste on one side of the slices.
With moistened hands, form the sushi rice into 8 uniform rectangular shapes and lay the fish slices on top.
For the shrimp sushi, cook the shrimp tails in boiling salted water over low heat for about 2-3 minutes. Rinse in cold water and drain.
Cut the shrimp down the ventral side and lay flat (do not cut all the way through the shrimp).
Pour the rice vinegar into a bowl and marinate the shrimp for 3 minutes, then remove and pat dry.
Spread the undersides of the shrimp thinly with wasabi paste.
With moistened hands, form the sushi rice into 8 uniform rectangles, and lay the shrimp on top. Arrange the sushi on plates and serve.