01 - In a large bowl, whisk together gochujang, soy sauce, sesame oil, honey, rice vinegar, garlic, ginger, brown sugar, and black pepper until smooth and well combined.
02 - Add chicken pieces to the bowl and toss thoroughly to coat evenly. Cover and refrigerate for at least 15 minutes, up to 2 hours for deeper flavor penetration.
03 - Preheat a large skillet or grill pan over medium-high heat until hot but not smoking.
04 - Shake excess marinade from chicken pieces and arrange in a single layer in the hot pan. Cook for 5 to 7 minutes per side, turning occasionally, until chicken is cooked through and edges are caramelized.
05 - Pour remaining marinade into the pan and reduce heat to medium. Simmer for 2 to 3 minutes, stirring constantly, until sauce thickens and coats the chicken pieces.
06 - Transfer chicken to a serving platter. Sprinkle with sliced green onions and sesame seeds. Serve hot alongside steamed rice.