1. Prepare the Chicken: Pat boneless, skinless chicken breasts or thighs dry with paper towels. Cut the chicken into uniform 1-inch cubes.

2. Mix the Marinade: In a medium bowl, combine the prepared teriyaki marinade, sesame oil, grated fresh ginger (if using), and minced garlic (if using). Whisk everything together until well combined.

3. Marinate the Chicken: Add the cubed chicken to the marinade, ensuring all pieces are thoroughly coated. Cover the bowl and refrigerate for at least 30 minutes, or up to 4 hours for deeper flavor.

4. Prepare Your Skewers and Grill: If using wooden skewers, soak them in water for at least 30 minutes. Preheat your grill to medium-high heat (about 400-450 F). Lightly oil the grill grates to prevent sticking.

5. Thread the Chicken: Thread the chicken pieces onto the skewers, leaving a small space between each piece to allow for even cooking. Do not overcrowd the skewers.

6. Grill the Skewers: Place the chicken skewers on the preheated grill. Cook for 5-7 minutes per side, turning occasionally, until the chicken is cooked through and has nice grill marks. The internal temperature of the chicken should reach 165 F.

7. Rest and Serve: Once cooked, remove the skewers from the grill and let them rest for a few minutes before serving. This allows the juices to redistribute, keeping the chicken tender and moist.