In a bowl, combine all the sauce ingredients—rice vinegar, water, orange juice, sesame oil, soy sauce, white sugar, brown sugar, white vinegar, orange zest, ginger, garlic, and hot pepper flakes. Whisk until well combined and set aside.

In a shallow bowl, whisk together the egg, salt, pepper, and one tablespoon of oil. In another shallow bowl, mix the cornstarch and flour.

Heat enough oil in a large frying pan over medium-high heat until hot (about 375°F).

Dip the chicken pieces into the egg mixture, then dredge in the flour mixture before adding them to the pan (make sure not to overcrowd the pan).

Fry for 3 to 4 minutes until golden and crispy. Transfer the cooked pieces to a cooling rack to drain excess oil.

Remove excess oil from the pan, leaving about one tablespoon. Stir in the prepared orange sauce and bring to a boil.

After boiling, turn off the heat and add the cooked chicken to the sauce. Stir until the chicken is well coated.

Plate it up with rice and garnish with orange zest, sesame seeds, and chopped green onions, if desired.