- Whisk together ingredients for sauce in a small bowl until cornstarch is dissolved. Slice chicken thighs into bite-sized pieces and trim off excess fat. Place chicken in a medium bowl and cover with ¼ cup of sauce. Allow to marinate for 10 minutes at room temperature.
- Heat 2 tablespoons of oil over medium-high heat in a large non-stick skillet for 2 minutes. Drain marinade from chicken and add chicken pieces to hot pan. Brown for 8 minutes, stirring occasionally. Transfer chicken to a bowl and discard liquid from pan. Carefully wipe pan dry with paper towel. Note: Chicken does not have to be fully cooked at this point.
- Reduce heat to medium and add remaining 2 tablespoons of oil to pan. Add zucchini, bell pepper, onion and chiles to pan and sauté for 5 minutes.
- Return chicken to pan and pour sauce over chicken and vegetables. Stir. Bring to a simmer and reduce heat to low. Simmer for 8-10 minutes, until sauce thickens and chicken is cooked through. Stir in peanuts during the last 2 minutes of cooking. Serve Kung Pao chicken hot with rice.