Make the Peppercorn Water: Steep 1 tsp of Sichuan peppercorns in 40ml of boiling water. Let it cool completely, then strain out the peppercorns. We only use the water.
Make the Dough: Combine 200g flour and 1g salt. Stir in 60ml hot boiling water, then 60ml cold water. Knead until smooth. Cover and rest for 20 minutes.
Season the Meat: In a large bowl, mix pork, minced ginger/scallion, white pepper, sugar, salt, light soy sauce, oyster sauce, and cooking wine.
Beat in Water: Stir the meat in one direction while gradually adding the cooled peppercorn water in 3 batches. Stir until the mixture becomes sticky and absorbs all liquid.
Add Chives: Coat the chopped chives with 1 tbsp oil (to seal in moisture), then mix them into the pork along with the sesame oil.
Roll Wrappers: Divide the rested dough into approx. 16 pieces. Roll each piece into a round, thin wrapper.
Assemble: Place filling in the center. Pinch the top edges together to seal, but leave the two ends slightly open (classic Guo Tie style).
Prepare Slurry: Whisk together the cornstarch, flour, salt, oil, and water for the crispy skirt.
Pan-Fry: Heat 1 tbsp oil in a skillet. Arrange potstickers and fry over medium heat until bottoms are pale golden.
Steam: Whisk the slurry again and pour it into the pan (it should reach 1/3 up the dumplings). Immediately cover with a lid.
Finish: Simmer until the water evaporates. Open the lid, sprinkle with sesame seeds/scallions, and fry for 1 more minute to crisp the bottom lace. Serve hot.