In a mixing bowl, whisk together soy sauce, brown sugar, honey, rice vinegar, mirin, minced fresh ginger, and garlic. Add gochujang and finely chopped scallions, stirring until the sugar fully dissolves.

Place the chicken thighs in a large bowl or resealable bag. Pour about two-thirds of the marinade over the chicken, ensuring each piece is coated. Marinate in the refrigerator for at least 30 minutes, or up to 4 hours.

Preheat your grill to medium-high heat, aiming for around 400°F.

Remove the chicken from the refrigerator and thread the pieces onto skewers, leaving space between each piece.

Grill the skewers for about 6-7 minutes on each side, basting with the remaining marinade halfway through.

Once grilled, let the skewers rest for a few minutes. Garnish with toasted sesame seeds and chopped scallions before serving.