In a medium bowl, whisk together gochujang, honey, lime juice, and soy sauce until smooth, Set aside.
Sprinkle chicken on all sides with salt, pepper, and chile flakes.
In another medium bowl, combine flour and cornstarch. Add chicken; toss to coat.
Add vegetable oil to a large skillet to a depth of about ¾ inch.
Heat oil until shimmering. Add chicken in batches; cook, turning occasionally, until browned
and crispy, 7 to 9 minutes per batch. Transfer cooked chicken to a wire rack.
Toss cooked chicken in sauce mixture to coat.
Sprinkle chicken with sesame seeds and green onion, if desired.