Combine all filling ingredients in a bowl and mix well by hand.
Place a teaspoonful of filling in a wrapper and put water along the edge of the wrapper. Make a semicircle, gathering the front side of the wrapper and sealing the top.
Heat oil in a frying pan. Put gyoza in the pan and fry on high heat for a min until the bottoms become brown. Add 1/4 cup water in the pan. Cover the pan with a lid and steam the gyoza for a few minutes on low heat.
Serve warm with gyoza sauce. Can be found in Asian food stores.