Chop cabbage, toss with salt, and rest 10 minutes to draw out moisture.
Squeeze cabbage very dry, then set aside.
Combine pork, scallions, ginger, garlic, soy sauce, sesame oil, wine, sugar, pepper, and cornstarch.
Stir filling in one direction until tacky, then fold in cabbage. Chill 10 minutes.
Set up wrappers, a damp towel, and small bowl of water.
Spoon 1 tablespoon filling onto a wrapper. Moisten rim, fold, and pleat to seal. Cover finished dumplings.
Boil method: Cook dumplings in plenty of boiling water until floating, then 2–3 minutes more. Drain well.
Pan-fry option: Brown in oil, add water, cover to steam until cooked, then uncover to crisp bottoms.
Stir soy sauce, rice vinegar, chili oil, and sesame seeds for dipping.
Serve dumplings hot with dipping sauce.