1. In a mixing bowl, combine chicken pieces and cornstarch. Toss to coat evenly.
2. Heat vegetable oil in a skillet over medium-high heat. Add chicken and cook until golden brown and cooked through, about 5-7 minutes. Remove chicken and set aside.
3. In the same skillet, add garlic and ginger. Cook for about 1 minute until fragrant.
4. Add soy sauce, orange juice, sugar, rice vinegar, sesame oil, and orange zest. Stir to combine and bring to a simmer.
5. Return the chicken to the skillet and toss to coat in the sauce. Cook for another 2-3 minutes until the sauce thickens and glazes the chicken.