01 - Whisk together soy sauce, brown sugar, sesame oil, rice vinegar, gochujang, garlic, ginger, and black pepper in a large bowl. Add chicken thighs and toss to coat thoroughly. Marinate for at least 15 minutes, or refrigerate overnight for maximum flavor penetration.
02 - 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 form and internal temperature reaches 165°F. Let rest for 5 minutes before slicing into strips.
03 - Divide cooked rice evenly among four bowls. Arrange sliced chicken, carrots, cucumber, purple cabbage, and green onions in sections over the rice. Sprinkle sesame seeds generously on top.
04 - Garnish with desired optional toppings such as kimchi, additional gochujang or sriracha, fresh lime wedges, or cilantro. Serve immediately while chicken is still warm.