Make filling: Chop cabbage to small pieces, sprinkle with 1 teaspoon of salt and toss well. Let stand 10 minutes, drain, then squeeze firmly to wring out excess moisture. In a large mixing bowl scatter cabbage and add pork. Sprinkle remaining filling ingredients on top. Using chopsticks, stir briskly in one direction until well-blended. Throw mixture against inside of bowl 5 to 6 times to compact it. Press plastic wrap on surface of filling and set aside 30 minutes at room temperature, or refrigerate up to 24 hours for flavor to develop. Bring to room temperature before using.
Fill one wrapper at a time, keeping remaining covered. Heap 1 level tablespoon filling off-center in wrapper and shape into a half-moon, about 2 inches. Run a moist finger lightly around edge of wrapper. Pleat and press dumpling closed. Transfer dumplings as they are made to a lightly-floured baking sheet and keep them covered with a towel to prevent drying.
Make sauce: About 20 minutes before serving, mix dipping sauce ingredients and season to taste.
Heat a heavy 12-inch cast-iron skillet with a tight-fitting cover over high heat. When very hot, add enough oil to coat bottom with a scant 1/4-inch, swirl skillet to coat bottom and sides, and reduce heat to medium. When oil is hot, pick up dumplings by their tops and quickly arrange them, smooth side down, in concentric rings starting from outside of pan and working into center. You will be able to cook about half of dumplings at a time. Dumplings should hug each other tightly in a pretty spiral; they will stick together. Adjust heat so they sizzle mildly. When all dumplings are in place, raise heat to brown bottoms. Check frequently, and when bottoms are browned, add enough stock to come halfway up sides of dumplings. Adjust heat to simmering and cover. After about 7 minutes, check to see if almost all stock has been absorbed. Check bottoms of dumplings -- they should be crisp enough to "clink" against a fingernail. If needed, add a little more oil down side of pan, swirl to distribute under dumplings and continue frying until crisp.
Loosen dumplings from bottom with a spatula and invert them onto a warmed serving platter, browned bottoms up -- they should cling in a spiral. Spoon dumpling sauce into individual saucers or dipping bowls and serve immediately. Do this in two pans at once, or repeat to cook remaining potstickers.