Nigiri Sushi (shrimp)

Skewer the shrimp on the underside from head to tail with toothpicks to prevent curling. Cook for 3 minutes in lightly salted boiling water, then transfer to ice water. When cool, remove the skewers and shell. Slit the underside of the shrimp open and cut through almost to the top but not completely to remove the dark vein. (In other words, butterfly the shrimp.) Moisten your hands with hand vinegar (a mixture of 1 cup water and 2 tablespoon vinegar). Take a small amount of the sushi rice (about 1 1/2 rounded tablespoons) and cradle it in your right hand at the base of your fingers. Crimp to form a rectangular block about 2-2 1/2 inches long with rounded edges and sides. Scoop up a very small amount of Wasabe horseradish with the tip of your finger and spread it on the inside of the shrimp. Place the shaped rice on top of the Wasabe and press gently with the index and middle fingers. Press in the sides, top, and bottom of the sushi, turning as necessary to hold its shape. Place on a platter shrimp side up and serve.