Combine cabbage and 1/2 teaspoon salt in a small bowl. Set aside for 10 minutes.
Meanwhile, add remaining filling ingredients to a bowl and mix well.
Remove cabbage from the bowl and squeeze out as much liquid as possible. Finely chop and add to pork and mix well.
Lay out 3 dumpling wrappers and place 1 tablespoon filling in each. Lightly rub the edges of the dumpling with water.
Fold the dumpling over the filling. Crimp the dumpling edges closed so it has pleats. Place on a parchment lined pan. Repeat with remaining filling.