In one bowl, whisk egg. In a separate bowl, combine cornstarch, flour, salt, and pepper. Dip each chicken piece into the egg, then thoroughly coat with the flour mixture.
Heat sufficient oil in a deep skillet or pan to 175°C. Fry chicken in batches for 5-6 minutes, until golden and crisp. Remove and drain excess oil on kitchen paper.
In a saucepan over medium heat with a splash of oil, sauté garlic and ginger for 30 seconds until aromatic. Add orange juice, soy sauce, rice vinegar, brown sugar, honey, sesame oil, and optional chili. Bring mixture to a simmer.
Stir in cornstarch slurry and simmer for 2-3 minutes until the sauce becomes glossy and thick. Add fried chicken and toss thoroughly until well coated.
Heat oil in a large wok or skillet. Sauté garlic until fragrant. Push to the side, pour in beaten eggs and scramble. Scatter in peas and carrots, then add cold rice. Stir-fry mixture for 3-4 minutes.
Pour soy sauce over rice and fold in green onions. Stir-fry for 1 minute until vegetables are heated through and grains separate.
Transfer fried rice to serving plates. Top generously with orange chicken. Garnish with sesame seeds, additional green onions, or orange zest if desired.