You can roast new potatoes from raw on your barbecue, but they will take a while to cook though. So pre boil them for speediness. If you dont have a barbecue you can always char them under the grill for a similar effect.
Pre heat the grill to high. Mix together the mustard, honey and soy sauce. Toss the potatoes in the mustard mixture and thread them onto skewers. Cook for 2-3 minutes on each side until charred crisp and golden brown.