Pat chicken dry and season with salt and pepper. Toss in cornstarch until evenly coated.
Heat oil in a deep skillet or wok over medium-high heat. Fry chicken in batches until golden brown and crispy, about 4–5 minutes per batch. Drain on a paper towel.
In a small saucepan, combine honey, soy sauce, garlic, ginger, and vinegar if using. Simmer gently until slightly thickened, stirring often.
Add chili flakes for spice if desired.
Toss fried chicken in the warm sauce until evenly coated.
Serve immediately with rice, noodles, or fresh greens.