Combine potato starch, flour, garlic powder, onion powder, salt, and pepper in a wide bowl. Whisk until evenly mixed.

Beat the eggs in a separate bowl. Dip each piece of chicken in the egg, let the excess drip off, then press firmly into the starch-flour mix, coating all sides.

Set dredged pieces on a wire rack and rest for 5 minutes so the coating bonds to the surface.

Pour oil into a deep heavy-bottomed pot and heat to 160 C / 320 F over medium-high heat. Use an instant-read thermometer to confirm.

Fry chicken in batches of 3 to 4 pieces for 7 to 8 minutes, turning once halfway, until the coating is set and pale golden. The chicken should reach an internal temperature of 74 C / 165 F.

Lift pieces onto the wire rack. Do not stack. Let the oil return to 160 C between batches.

Combine gochujang, soy sauce, honey, rice vinegar, minced garlic, grated ginger, and water in a small saucepan over medium heat.

Stir continuously for 3 to 4 minutes until the glaze thickens slightly and becomes glossy. Remove from heat and stir in the sesame oil. Set aside.

Raise the oil temperature to 190 C / 375 F. Fry the chicken again in batches for 3 to 4 minutes until the exterior is deep golden and audibly crisp when tapped.

Transfer back to the wire rack and wait 60 seconds before glazing.

Place all fried chicken pieces in a large mixing bowl. Pour the warm glaze over and toss quickly to coat every piece evenly.

Transfer to a serving plate. Scatter sesame seeds and sliced scallions over the top. Serve immediately.