Cut the pork into 1-inch cubes. Put the cubes into a bowl together with the rice wine or sherry, 1 tablespoon of light soy sauce and 1/2 teaspoon salt and marinate for 20 minutes.
Meanwhile, cut the green and red bell peppers into 1-inch squares. Peel and cut the carrot and scallions into 1 inch chunks. Uniform size of meat and vegetables is important to the presentation as well as ease of cooking. Bring a pot of water to a boil and blanch the carrots in it for 4 minutes; drain and set aside.
Mix the egg and cornstarch in a bowl until they are well blended into a batter. Lift the pork cubes out of the marinade, put them into the batter, and coat each piece well. Heat the oil in a deep fryer or large wok until it is almost smoking. Remove the pork pieces from the batter with a slotted spoon, and deep-fry them. Drain on paper towels.
Combine the chicken stock, soy sauce, salt, vinegar, sugar, and tomato paste in a large saucepan. Bring it to a boil. Add all the vegetables, but not the lychees or oranges, and stir well. In a small bowl, blend together the cornstarch and water. Stir this mixture into the sauce and bring it back to a boil. Turn the heat down to a simmer. Add the lychees or oranges and pork cubes. Mix well, and then turn the mixture onto a deep platter and serve at once with plain steamed rice.