well. Add 1- half tablespoons oil and mix well again. Place the shrimp in a bowl and refrigerate at least 2 hours.Remove the shrimp and dust with remaining cornstarch. Shrimp should be dry to the touch. Heat the remaining oil in a large wok to 350 to 375 degrees. Fry the shrimp 1- half to 2 minutes until crisp, being careful to separate them with a longhandled wooden spoon or chopsticks to prevent sticking. It may be necessary to fry the shrimp in several batches. When done, remove the shrimp with a slotted spoon and drain well. Combine the shrimp and the sweet and pungent sauce and toss quickly to coat. Immediately turn out onto a platter and sprinkle with finely chopped green onions. SWEET AND PUNGENT SAUCE: Combine the sugar, catsup, vinegar, and salt, and set aside. Heat the oil in a wok. Add the garlic, ginger, green onion, red pepper, and zests of lemon and orange; cook 30 seconds. Stir in the sugar-catsup mixture. Immediately add the sherry mixture and cook until slightly thickened.