In a medium bowl, whisk together the egg, garlic powder, cayenne pepper, and oil with a fork until almost frothy, about 1 minute. Add the chicken to the mixture and allow sitting for 10 to 15 minutes. For the sauce: Meanwhile, combine the sauce ingredients in a small bowl, and set aside. To Cook: In a large ziplock bag, add the cornstarch. Add the marinated chicken into the bag, seal, and shake until fully coated. Heat the oil in a wok or large nonstick skillet over medium-high heat until hot, and once it just begins to smoke, add the marinated chicken. Cook without touching the chicken until the bottom turns golden brown, about 2-3 minutes. Flip to brown the other side for 2 to 3 minutes. Transfer chicken to a big plate and remove the pan from the stove. Let cool for 2 to 3 minutes. Place the pan back onto the stove and turn to medium heat. Wipe the skillet with a paper towel, leaving about 1 to 2 tablespoons of oil in the skillet. Add the dried chili, the white part of the green onion, ginger, and garlic. Stir-fry until it releases its fragrance, about 1 minute.

Stir the sauce again to dissolve the cornstarch completely. Pour into the pan along with the green part of the green onion. Stir and cook until it thickens.

Add the chicken pieces back to the skillet and toss to coat the chicken with the sauce. Garnish with sesame seeds, if desired. Transfer the Orange Chicken to a plate and serve over white rice. Enjoy!