In a bowl, whisk together soy sauce, brown sugar (or honey), rice vinegar, sesame oil, garlic, and ginger.
Reserve ¼ cup of the sauce for brushing later.
Add chicken to the remaining marinade, toss to coat, cover, and refrigerate for at least 30 minutes.
Thread marinated chicken onto skewers.
Preheat grill to medium-high heat (or use grill pan).
Grill skewers for 10–12 minutes, turning occasionally, until chicken is cooked through.
Brush with reserved sauce during the last 2–3 minutes for a glossy finish.
Garnish if desired and serve hot.