In a medium bowl, mix the sugar, soy sauce, pepper, garlic, lemon grass and sesame seeds. Place the meat in the dish, and stir to coat. Cover and refrigerate for 4 hours.
Discard marinade and thread the meat onto skewers accordion style.
Preheat the barbecue to high and brush with oil. Put the skewers on the barbecue and cook 5 minutes per side. Serve them hot or remove the meat from skewers and serve on lettuce leaves with rice noodles. Garnish with coriander, mint, Thai basil, and sliced spring onions.