While the chicken is cooking, prepare the sauce. Heat the sesame oil over medium heat in a small saucepan. Add the garlic and ginger, and cook for 2-3 minutes or until fragrant. Add the orange juice, soy sauce, vinegar, zest, chili flakes, and sugar. Stir and bring to a light boil. In a separate small bowl, whisk together the cornstarch and water. Add the mixture to the saucepan and stir for 1-2 minutes or until thickened. Remove from heat immediately.
2 teaspoons toasted sesame oil*, 4 cloves garlic, 1 teaspoon ginger paste, 1/3 cup fresh orange juice, 2 Tablespoons EACH soy sauce, 1 teaspoon orange zest, 1/2 teaspoon red pepper flakes, 1/3 cup granulated sugar, 1 Tablespoon cornstarch, 2 tablespoons water