Slice the cabbage leaves into strips 1/2 inch wide and the base about 1/8 inch wide. Measure 4 cups into a colander. Sprinkle lightly with salt, toss, and set aside for an hour.

Meanwhile, cover the dried mushrooms generously with boiling water and let soak for 15 minutes. Squeeze dry, remove the stems, and slice the caps into thin strips. Reserve the soaking liquid.

Squeeze out the excess moisture from the cabbage. It shouldn't be necessary to rinse it, but taste to make sure.

Combine the cabbage, dried and fresh mushrooms, leek, garlic, ginger, and vinegar. Add Sichuan pepper salt to taste and more vinegar if needed to bring up the flavors.

Put a spoonful of the filling in the middle of a wonton wrapper, paint the edges with water, and fold the opposite corners together. Use as much filling as you can and still be able to close the dumpling. Make two or three pleats on each side, then set the dumpling down firmly to make a solid, flat bottom. Repeat with the remaining filling and wrappers. Cover with a barely damp towel until ready to cook.

To steam the dumplings, lightly oil the surface of the steamer, set the dumplings on top, and bring the water to a boil. Cover and steam for 7 minutes.

To fry the dumplings, coat a 12-inch cast-iron skillet generously with peanut oil, add the dumplings, and fry over medium-high heat until golden on the bottom. Add enough of the reserved mushroom soaking liquid, plus water if needed, to come about one-third up the side of the dumplings-stand back-and cover until the hissing subsides. Boil briskly until the liquid is reduced and the potstickers begin to fry again. Now is when they stick to the pot. Turn off the heat and gently loosen them with a thin metal spatula.