Heat oil in medium skillet over medium-high heat until hot. Add chicken; cook 5 to 7 minutes or until browned, stirring frequently. Stir in cucumber, carrot, peanuts, gingerroot and garlic. Stir in reserved sauce with cornstarch. Cook 2 to 3 minutes or until bubbly and thickened, stirring constantly. Spoon mixture into shallow dish. Cover; refrigerate 30 minutes or until cooled.