01 - In a medium mixing bowl, whisk together soy sauce, mirin, honey, rice vinegar, grated ginger, minced garlic, sesame oil, and ground black pepper until thoroughly combined.
02 - Transfer 3 tablespoons of marinade to a small bowl and set aside for basting during grilling.
03 - Place chicken cubes in a large zip-top bag or bowl. Pour the remaining marinade over the chicken. Seal or cover and refrigerate for at least 1 hour, up to 8 hours for enhanced flavor.
04 - Preheat grill or grill pan to medium-high heat.
05 - Thread marinated chicken pieces onto the skewers, leaving a slight gap between each piece to ensure even cooking.
06 - Grill chicken skewers for 10 to 12 minutes, turning occasionally and basting with reserved marinade, until cooked through and lightly charred.
07 - Transfer grilled skewers to a serving platter. Sprinkle sesame seeds and sliced green onions over the top if desired. Serve hot.