Set up a food processor and combine the shrimp, ginger, scallions, soy sauce, sesame oil, egg whites and corn starch in its bowl. Puree them all together until it is a smooth, thick filling. Dollop 2 teaspoons of that filling into the center of a wonton wrapper, then bring up the sides and pleat them to look like a little drawstring purse. The filling should peek out a little. Place it under a clean, wet cotton towel to keep the wrapper from drying out. Repeat this until you have made 24 little shu mai total.

Find a deep skillet or wok that fits your 2 tiered bamboo steamer and fill it about halfway with water, making sure the steamer doesn't touch the water. Bring it to a simmer over medium to medium high heat, but don't let it come to boil. Line each tier of the bamboo steamer with either parchment paper, lettuce leaves or cabbage leaves to keep it clean, then fill each tier with 12 of the shu mai. Close the steamer with its lid and place it over the simmering water. Let the shu mai steam for about 8 minutes or so, until the filling is opaque and cooked through. Serve immediately with soy sauce for dipping!