To make orange sauce: Add orange juice, granulated sugar, rice vinegar, gluten free soy sauce, ground ginger, and garlic powder to a large pot, or wok, and heat over medium heat for 3-5 minutes.
In a small mixing bowl, whisk 1 tablespoon of cornstarch with 2 tablespoons of water to form a paste. Add the paste to orange sauce and whisk together.
Continue to cook for 5 minutes, until the sauce begins to thicken.
Once the sauce is thickened, remove from heat and add the orange zest. Stir until combined; set aside.
To make chicken: In a shallow dish, combine gluten-free flour and cornstarch and stir to combine.
Whisk eggs in separate shallow dish.
Dip chicken pieces in egg mixture, coating all sides, and then in the flour mixture, coating all sides. Place on a separate plate. Repeat until all chicken is coated.
Heat 2-3 inches of oil in a heavy-bottomed pot over medium-high heat until shimmering.