Heat oil in lg skillet, over med-high heat. Add chicken. Brown on all sides for about 5-7 mins.
In bowl, combine 3/4 cup water, soy sauce, brown sugar, ketchup, vinegar, garlic and ginger. Mix well and stir into chicken in skillet.
Bring to a boil. Cover, reduce heat to low and simmer 15 mins, stirring occasionally. In small bowl, combine cornstarch and 1 tbsp water until smooth. Stir into skillet and cook until sauce thickens. I serve this over rice.