Cut chicken into 1 inch squares, combine with soy sauce and garlic; let stand 15 minutes. Heat vegetable oil in a large skillet over medium-high heat. Coat chicken with the cornstarch and cook in a single layer, 1 minute on each side. Add the crushed red pepper, cook and stir 1 minute. Turn off heat; stir in orange sauce. Garnish with green onions and sesame seeds.