1) In a small bowl, combine hoisin sauce and vinegar; set aside. In another small bowl, mix together cornstarch and 1 tablespoon of water until smooth. Add chicken to the mixture and toss to coat.

2) In a large skillet or wok, heat 1 tablespoon oil over medium-high. Stir-fry half of the garlic and vegetables for about 3 minutes; set aside. Repeat with the remaining oil and garlic. Remove chicken from pan; return vegetables to the pan.

3) Add sauce to the skillet and cook, stirring constantly, until bubbling. Add chicken and cook for 2 minutes or until chicken is cooked through. Serve over rice.