In a large colander set over a bowl, toss the cabbage with 1 tablespoon salt and let sit for 5 to 10 minutes. Squeeze to remove the liquid.
Meanwhile, in a large bowl, combine the flour and remaining 1 1/2 teaspoons salt. Using your fingers, slowly mix in 1 cup plus 2 tablespoons cold water to form a dough. Knead until smooth, about 5 minutes. Cover with plastic wrap and let rest for at least 30 minutes.
In another large bowl, combine the pork, egg, scallions, garlic, ginger, cornstarch and sugar. Stir in 1 tablespoon soy sauce and 1 teaspoon sesame oil. Add the cabbage and stir the mixture vigorously, adding about 1/4 cup cold water, to form a paste.