Whisk the flour, cornstarch, salt, and pepper together in a bowl.
Dip chicken pieces into the beaten eggs, then coat with the flour mixture.
Heat oil in a deep pan and fry chicken in batches until golden and crispy. Drain on paper towels.
In a saucepan, combine orange juice, sugar, soy sauce, rice vinegar, garlic, and ginger. Bring to a simmer.
Add orange zest and stir in the cornstarch slurry until the sauce thickens.
Toss fried chicken with the sauce until coated.
Serve hot, garnished with sesame seeds and green onions.