01 - In a large bowl, whisk together soy sauce, brown sugar, sesame oil, rice vinegar, gochujang, garlic, ginger, and black pepper until the sugar dissolves completely.
02 - Add chicken thighs to the bowl and toss to coat evenly. Let marinate for at least 15 minutes at room temperature, or refrigerate overnight for deeper flavor penetration.
03 - Heat vegetable oil in a large grill pan or skillet over medium-high heat. Remove chicken from marinade, allowing excess to drip off. Cook chicken for 4-5 minutes per side until charred edges develop and internal temperature reaches 165°F.
04 - Transfer cooked chicken to a cutting board and let rest for 5 minutes to allow juices to redistribute. Slice against the grain into thin strips.
05 - Divide cooked rice evenly among four bowls. Arrange sliced chicken, carrots, cucumber, cabbage, and green onions in sections over the rice. Sprinkle with sesame seeds.
06 - Top with kimchi, additional gochujang or sriracha, lime wedges, and fresh cilantro as desired. Serve immediately while chicken is still warm.