Combine chicken, scallion, leek, ginger, sherry, sugar, soy sauce, sesame oil, egg, pepper and salt and mix. Place 2 tsps. of the filling into a homemade or store bought dumpling wrapper. Dab the edges with water and press firmly to form a tight seal. Set aside. Coat a large, deep skillet with a thin layer of oil and turn the heat to medium-high. Place dumplings in one at a time seam side up leaving space in-between. (you most likely will need to do this in 2 batches). Turn the heat to medium cover and cook for about 5 mins. Add 1/2 c. of water to skillet and then cover for another 2 mins. Remove the lid and cook until the water evaporate, appx. 3 mins. Remove the dumplings and serve with your choice of dippings sauce(s) :o)