this (with hubby's help on the grill) today and it was amazing. We got really good quality chicken breasts which I think made the difference.
Make sure you use negi, as in long tokyo onion (naga negi). Do not use leeks- they are too tough! You can tell the difference because negi will be less than 3/4 inch diameter.
You make a marinade/basting sauce (see the recipe) which is quite similar to teriyaki and the chicken rests in it for 10-20 minutes. Then thread onto skewers with the 1" pieces of leek. Barbecue until done.