To make the infused water, in a bowl combine the Sichuan peppercorns, scallions, and ginger. Pour in the hot water and allow it to infuse for a few minutes, then strain and set aside.
To make the filling, in a bowl combine the ground pork with the salt, white pepper, soy sauce, dark soy sauce, oyster sauce, Shaoxing wine, and cornstarch. Gradually mix in the infused water in two additions until the pork becomes smooth and slightly sticky. Add the cabbage, scallions, and cooking oil and mix until evenly combined.
To wrap the dumplings, place a dumpling wrapper on a flat surface and brush the edge with water. Add about 2 teaspoons of filling to the center, fold the wrapper in half, and press the edges together to seal.
To make the dipping sauce, in a bowl combine the soy sauce, Chinkiang vinegar, and chili oil and mix well.
To cook the dumplings, bring a large pot of water to a boil over high heat. Add the dumplings and gently stir to prevent sticking. Cover until the water returns to a boil, then uncover. Add ½ cup water and allow the pot to return to a boil. Repeat this process two more times until the dumplings are fully cooked, about 8 minutes.
Serve hot with the dipping sauce.