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