Make the sauce: In a small saucepan, combine honey, soy sauce, 2 tbsp water, vinegar, sesame oil, and optional red pepper flakes. Bring to a simmer over medium heat.
In a separate bowl, stir together the cornstarch and 1 tbsp cold water to make a slurry. Slowly whisk this into the simmering sauce. Cook 2–3 minutes until thickened. Reduce to low to keep warm.
Prepare the chicken coating: In a shallow bowl, mix flour, cumin, chili powder, coriander, and onion powder. In a second bowl, pour the buttermilk.
Coat the chicken: Working with a few pieces at a time, dredge chicken in flour, dip into buttermilk, then back into the flour. Press to adhere coating well.
Fry the chicken: Heat oil in a large deep skillet over medium-high. Once shimmering, carefully fry chicken in batches, 5–7 minutes per batch, turning as needed until golden brown and internal temp reaches 165°F. Drain on paper towels.
Toss and serve: Place fried chicken into a large mixing bowl. Pour the warm honey sauce over the chicken and gently stir to coat.
Serve hot: Best with steamed rice and a sprinkle of green onions.