Mix the flour with water and knead for about 15 minutes, or until the dough becomes soft. Divide the dough into two equal portions and roll each into a cylinder, approximately 1 inch (2.5 cm) in diameter. Cover the cylinders with a wet towel and set aside.
Prepare the chives by trimming off the root or white part, using only the green section. Mix the chopped chives with the ground pork and add all the ingredients for the filling. Stir to combine thoroughly.
Cut the dough into pieces approximately 1/4 inch (5 mm) in length. Use a rolling pin to flatten each piece until it forms a round shape about 3 inches in diameter.
Place a small spoonful of filling in the center of each skin and seal it tightly with your fingers (no pleating is needed for this recipe). Repeat the process until all the ingredients are used up.
Bring a pot of water to a boil. Carefully drop the dumplings into the boiling water and cover the pot. Once the dumplings start to float (indicating they are cooked), use a strainer to dish them out onto a serving platter. Serve hot with black vinegar.