Break the eggs into a bowl and use chopsticks to beat the eggs until they break thoroughly. Add salt, sesame oil, shaoxing wine, white pepper powder, and lightly beat to blend well. Set aside. Heat up a wok with 2 tablespoons cooking oil. Add the egg mixture into the wok, and use your spatula to spread the eggs. Keep stirring until the eggs form lumps. Gently break the lumps into smaller pieces. As soon as the eggs are cooked, dish out and set aside. Clean the wok and heat it up again with 1 tablespoon cooking oil. Drop the tomato wedges into the wok and do a few quick stirs. Add sugar and water into the tomatoes. Cover it with the lid and let it cook for about 30 seconds. Transfer the eggs and chopped scallions into the tomatoes, stir-fry for 30 seconds or so, dish out and serve immediately.