Make potsticker dough: Divide flour into 2 separate bowls. Bring 1/2 cup water to a boil, measure out 1/4 cup plus 2 tablespoons water and stir into 1 bowl to form a dough. Stir 1/4 cup cold water into second bowl to form a soft dough. Combine both doughs and knead together until they are smooth, about 15 minutes. Cover with a damp towel and let stand 15 minutes.

Make filling: In a large pot of boiling salted water, cook Napa cabbage just until wilted, about 1 minute. Drain in a colander, refresh under cold running water and squeeze dry. In a food processor combine cabbage, pork, 1 tablespoon of green onions, ginger, sherry, 1 1/2 teaspoons soy sauce, 1 1/2 teaspoons sesame oil and salt; process just until combined. Remove to a bowl, cover and refrigerate 30 minutes.

Make potstickers: On lightly-floured work surface divide dough into 4 parts. Roll each part into a long thin rope, 1/2-inch in diameter. Cut each rope into 12 pieces. Roll each piece between your palms to form a smooth ball. Sprinkle lightly with flour and use a small rolling pin to flatten into 3 inch pancakes. Spoon about 1 teaspoon filling into center of each pancake, fold over in a half moon shape, and seal with water. Repeat until all dumplings are filled.

Make dipping sauce: In a small bowl combine remaining tablespoon green onion, 1/2 cup soy sauce, 1 tablespoon sesame oil, chili garlic sauce until blended.

In a large nonstick skillet, heat vegetable oil over medium-high heat. Add as many dumplings as will fit in skillet without touching and brown bottoms 1 to 2 minutes. All at once, add enough cold water to cover bottom of pan, cover immediately and bring to a boil. Cook until tops of dumplings are waxy and cooked through, about 5 minutes. Water will evaporate (if some water remains, drain water), heat and continue cooking until bottoms of dumplings are brown and crisp, about 2 minutes; keep warm. Repeat with remaining dumplings. Serve immediately with dipping sauce.