Season chicken pieces with salt and pepper. Dip in beaten eggs, then dredge in a mixture of flour and cornstarch.
Heat oil in a deep-fryer or large skillet to 350°F. Fry chicken pieces until golden and crispy, about 3 to 5 minutes. Drain on paper towels.
In a saucepan, sauté garlic and ginger in olive oil until fragrant. Add orange juice, orange zest, sugar, soy sauce, rice vinegar, and chili flakes. Bring to a simmer over medium heat.
Make the cornstarch slurry by dissolving the cornstarch in the water. Add it to the sauce mixture and cook until thickened, about 5 to 10 minutes.
Toss fried chicken with the orange sauce until evenly coated. Serve immediately.
