Devein the shrimp and remove the tail. Rinse under cold water, put paper towels on a cookie sheet, and dry with additional paper towels. Add the cornstarch and mix well.
Mix together the vinegar, sugar, salt, and soy sauce in a small bowl
In another bowl, add the garlic, ginger, and the white part of the scallions
Add 1/4 cup oil to the wok and turn the heat to high. When hot, add the shrimp. Stir fry until pink, about 2 minutes. Remove and drain on a paper towel.
Add two tablespoons of oil and heat for 30 seconds, and add the ginger, garlic, and white part of the scallions.
Add the vinegar and soy sauce mixture and boil. Add the shrimp and stir until coated in the sauce.
Remove and serve with white rice