A good teriyaki sauce gives grilled chicken a rich auburn color. My homemade version includes just the right amount of ginger to give it an equally appealing taste. While you can also use boneless breasts for this recipe, boneless thighs stay moister during grilling.
Place the chicken thighs in a gallon-size zip-lock bag and add the marinade ingredients. Press the air out of the bag and seal it. Turn the bag to thoroughly coat the chicken, then place it in a bowl and refrigerate it for at least 4 hours (preferably overnight), turning the bag occasionally. Remove the meat from the refrigerator 20 minutes before grilling.
Prepare a charcoal fire or set a gas grill to medium-high, close the lid, and heat until hot -- about 10 to 15 minutes.
Remove the chicken from the bag and discard the marinade. Grill the thighs until they are no longer pink inside, about 5 minutes per side on a gas grill.
Transfer the thighs to a cutting board and let them rest for about 5 minutes, then slice each piece at a diagonal. Sprinkle on the toasted sesame seeds. Serve over rice, garnished, if you like, with scallion strips. Serves 6 to 8.