01 - In a medium mixing bowl, whisk together soy sauce, mirin or sherry, honey or brown sugar, rice vinegar, grated ginger, minced garlic, sesame oil, and black pepper until well blended.
02 - Separate 3 tablespoons of the marinade and set aside in a small bowl for basting during grilling.
03 - Place cubed chicken in a large zip-top bag or bowl. Pour remaining marinade over the chicken, seal or cover, and refrigerate for a minimum of 1 hour and up to 8 hours for optimal flavor.
04 - Preheat grill or grill pan to medium-high heat ahead of assembly.
05 - Thread marinated chicken pieces onto skewers, ensuring space between pieces to promote even cooking.
06 - Arrange skewers on the grill and cook for 10 to 12 minutes, turning occasionally and brushing with the reserved marinade until chicken is fully cooked and lightly charred.
07 - Transfer cooked skewers to a serving platter. Sprinkle with sesame seeds and green onions as desired. Serve immediately while hot.