Prepare the Wonton Filling: Cut the napa cabbage into thin strips, then finely chop across. Mix with sea salt in a large bowl and let sit for 30 minutes to draw out moisture. Once softened, squeeze out all liquid by hand.
Mix the Filling: In a separate bowl, combine ground pork, 2 tablespoons of water, neutral oil, sesame oil, Shaoxing wine, soy sauce, ginger, sugar, and white pepper. Mix vigorously with chopsticks for about 10 minutes, or use a stand mixer on low for 5 minutes until the mixture becomes paste-like. Stir in the drained cabbage until fully incorporated.
Assemble the Wontons: Line a sheet pan with parchment paper. Fill a small bowl with water. Place a wrapper in your palm, spoon in 1 heaping teaspoon of filling in the center, and moisten the edges. Fold and seal into desired shape, pressing edges together firmly. Repeat until all wrappers are used.
Freeze (Optional): If not cooking immediately, freeze wontons on the sheet pan in a single layer. Once solid, transfer to freezer bags and store for up to 3 months.
Prepare the Sauce: In a wide, heatproof bowl, spread half the garlic, sugar, and Sichuan pepper. In a small saucepan, heat neutral oil until shimmering. Carefully pour hot oil over garlic and spices (it will sizzle). Stir in chili oil, soy sauce, sesame oil, and the rest of the garlic.
Cook the Wontons: Bring a large pot of water to a rolling boil. Stir to keep the wontons from sticking. Add 15 wontons at a time and boil for 4 to 5 minutes (or 5 to 6 minutes if frozen) until they float and are cooked through. Add ¼ cup cold water if it boils too vigorously to slow the cooking and ensure the filling heats through. Once done, cook 1 more minute, then remove with a slotted spoon.
Serve: Toss hot wontons in the prepared sauce. Garnish with toasted sesame seeds, scallions, and cilantro if using. Serve immediately.