Combine egg, salt, and cornstarch in a bowl and beat well with a wire whisk. Do not make it frothy. Pour mixture through a fine strainer.
Heat an 8-inch nonstick skillet or crepe pan and lightly grease with vegetable oil. Pour half the egg mixture into the pan and immediately tilt the pan to swirl the mixture around to form a very thin crepe.
Cook over low heat for about a minute, until the egg is firm enough to turn over. Do not brown the crepe. Cook the other side for about 30 seconds and remove to a board or plate to cool.
Cut into strips about 1/4 inch wide and 2 inches long. Set aside. They will keep for several hours.