In a medium bowl, add the ground pork, cornstarch, white pepper, water, neutral oil, oyster sauce, and sesame oil. Mix well, and set aside to marinate for 15 minutes while you prepare the rest of the dish.

Heat a wok over medium heat until lightly smoking. Add the neutral oil to the wok, along with the string beans. Toss the string beans to coat in the oil, and sprinkle with the salt. Cook for 2 minutes uncovered, and then for 7-10 minutes covered, tossing periodically with a wok spatula. They should be lightly blistered and bright green.

Transfer the beans to a dish, leaving behind as much oil as you can. Add the pork to the wok and brown until lightly golden. Add the garlic and fry for 1 minute or so. Add the zha cai.

Deglaze the wok with the Shaoxing wine. Add the green beans back in along with the scallions, followed by the light soy sauce, oyster sauce, dark soy sauce (if using), and sugar. Stir-fry to combine until everything is uniformly seasoned. Serve!