• Before you start the dough, prep the cabbage: Toss the cabbage with ½ teaspoon salt and place it in a colander to drain for 20 minutes while you make your dough.

For the Dough

• Place flour in a medium bowl. Pour the boiling water over the flour, mixing to combine. Turn the dough out onto the counter and knead for 10 minutes. (Don't skimp on the kneading time, this will develop the gluten proteins that give the dough its texture.)
• Shape the dough into a 1 inch diameter snake. Cover the dough with a damp tea-towel and let rest for 30 minutes.

For the Filling

• In a medium bowl, mix together pork, sliced leeks, soy sauce, vinegar, ginger, and salt.
• Press any excess moisture out of the cabbage and add it to the pork mixture. Mix well and set aside.

Making the Dumplings (Jiaozi)

• Cut the snake into ½ inch pieces. Keep the dough pieces you are not working with covered with the damp towel.
  
• Roll one piece of dough into a roughly 3 inch diameter circle. Fill with 2 teaspoon of filling and spread a little water on the outside edge of the circle of dough.
• Fold the dough around the filling and crimp the edges by folding one side over itself 5-7 times and pressing it against the opposite side of the dough. (See the pictures below.)
  
• Set the dumpling on a plate and continue with the remaining dough.*
  

Making Potstickers (Guotie)

• Heat ½ teaspoon oil in a large skillet with a lid. Place dumplings in a single layer in the skillet, so they are not touching. Cook the dumplings in the oil over medium-high heat, until crisp, 1-2 minutes.
• Add ½ c of water to the pan and cover tightly. Reduce the heat to low and cook 5-7 minutes, until most of the water has steamed out.
• Uncover and cook until any remaining water has evaporated, 1-2 min.
• Serve immediately with a dipping sauce.