Put the chopped tomato, salt, white pepper powder, light soy sauce, sesame oil, black vinegar, dried shrimp flakes (if using), and scallion (or cilantro) into your noodle bowl.
Pre-heat a pan or wok until it starts to smoke, and spread the oil around to coat. Fry the egg to your liking, dish it up, and set aside.
Boil the water in a medium pot (or your wok), and add the noodles. When the noodles are almost done cooking, transfer 1½ cups of the noodle cooking water to the noodle bowl. Add the leafy greens to the pot/wok with the noodles. Once the noodles and greens are cooked, add them to the bowl. Top with the fried egg, and enjoy.