Cut the chicken thighs into small bite-sized pieces that are about 1-inch cubes.
In a bowl combine egg, salt, ground white pepper, cornstarch, all-purpose flour, water, and vegetable oil. Stir to combine.
Place cut chicken thighs into the batter. Stir to coat the chicken thighs very well with the batter. Cover bowl with plastic wrap and place into the refrigerator for 30 minutes.
Place vegetable oil into a pot, the vegetable oil should be at least 4 inches deep. You can use a deep fryer. Heat the oil to 350°F.
Shake off excess batter off chicken and fry pieces until they become light golden brown, this should take 6 to 7 minutes. You will need to fry the chicken in small batches. When you remove the chicken from the oil, drain on a wire rack resting on a cookie sheet.
In a small bowl combine orange juice, soy sauce, ginger, ground white pepper, vinegar, cornstarch, sugar, chili flakes in oil, and sesame oil. Whisk together well.
Pour sauce into a large skillet or wok, turn the heat up to medium high and cook until the sauce thickens. Add cooked chicken and stir to coat.
