Toss the cabbage with the salt and let it sit 10 minutes. Squeeze out as much water as you can in a clean towel.
In a medium bowl, mix the pork, cabbage, scallions, garlic, ginger, soy sauce, oyster sauce, sesame oil, sugar, and red pepper flakes until just combined.
Keep the wrappers covered with a damp towel. Place about 2 teaspoons of filling in the center of a wrapper.
Wet the edge with water, fold in half, and pinch to seal, pleating if desired. Press out any air. Repeat with the rest.
Preheat the air fryer to 380°F.
Spray the basket. Arrange the dumplings in a single layer, not touching, and spray the tops.
Air fry for 5 minutes. Flip, spray again, and air fry 3 to 5 minutes more, until golden and the filling reaches 160°F.
Rest 2 minutes and serve with dipping sauce. Repeat with remaining dumplings.