2. Puree the shallots, garlic, ginger and chili pepper in a food processor.
3. Heat the oil in a small saucepan over medium heat. Add the shallot mixture and lemon grass and cook, stirring occassionally, for 5 minutes. Remove from heat.
4. Add the remaining ingredients for the marinade, set aside and let cool.
5. Meanwhile, mix the ingredients for the yogurt sauce together, cover and refrigerate.
6. When the marinade has cooled, cut the chicken into 16 1-inch wide strips, pour the marinade over the chicken and coat well. Cover and refrigerate for 20 minutes.
7. Preheat the grill. Skewer each piece of chicken with one of the skewers. Place the chicken on the grill and cook for about 2 minutes on each side, until the chicken is cooked through. Serve the chicken with the yogurt sauce.