Put the flour in a mixing bowl and gradually add the boiling water while mixing the dough with wooden chopsticks or a wooden spoon. The hot water will slightly cook the flour and it will form lumps. Continue to mix for about half a minute then add the cold water. At this point start using your hands to knead the dough. It will be sticky initially. Knead the dough until it is elastic and smooth. Let the dough rest for about half an hour before use. Cover the dough with a damp cloth or seal it with plastic wrap.
Chop the garlic chives into small pieces of about 1/8 inch. Mix all the stuffing ingredients together and set aside.
Divide the dough into three equal portions. Roll each portion into a cylinder about 1/2 inch in diameter. Cut the cylinder into pieces about 1/2 inch wide. Roll the pieces into balls. Flatten the balls into rounds and roll them into wrappers with a Chinese rolling pin. When rolling the wrapper use one hand to roll the pin back and forth, while using the other to push the round dough under the rolling pin. Turn the dough about one quarter turn just after the rolling pin presses down on the dough. Repeat until the dough becomes a thin round wrapper. Fill with about 1 tablespoon of stuffing. Pleat the edges into a crescent shape dumpling and press to seal.
You will need a thin Chinese rolling pin of about one inch in diameter to roll the wrappers. It is often available in Chinatown markets or from mail order outlets. You can use a regular baking rolling pin but manipulating the wrappers under this thicker bulky version can be tricky.
Pour about 1/8 inch layer of vegetable oil in a frying pan then arrange the dumplings in the cold oil. It is fine to arrange the dumplings touching each other. Fry the dumplings on medium heat for about one minute. Add 1/2 cup of warm water to the pan and cover. Let steam for about three minutes or until all the water has evaporated. Uncover the pan and let the bottom of the dumplings continue to brown. As they brown they will loosen from the pan and can be flipped onto a plate. Serve with thinly shredded ginger in Chinkiang black vinegar.