Step 1 In a small bowl, toss cabbage and salt together. Set aside for at least 10 minutes to draw water out of the cabbage.
Step 2 Meanwhile, combine the soy sauce, rice wine and sugar in a medium bowl until sugar is dissolved. Vigorously stir in the pork and sesame oil, using a fork or chopsticks and stirring in one direction until the mixture becomes a smooth paste. Gradually add the water in 3 stages, vigorously stirring in the same direction until each addition is emulsified.
Step 3Squeeze the excess water from the cabbage with your hands and transfer to a plate, reserving the water. Add the cabbage water to pork mixture, vigorously stirring in the same direction; the mixture will be very soft. Stir in the drained cabbage and ginger. Use the filling immediately, or wrap and chill until ready to use, no more than 1 day.