1.Blend or process oil, preserved lemon, juice, garlic, ginger, spices, sugar and half the marjoram until almost smooth. Reserve 1 tablespoon of paste.
2.Combine chicken with remaining paste in large bowl. Cover; refrigerate 3 hours.
3.Thread chicken onto six metal skewers. Cook skewers on heated oiled grill plate (or grill or barbecue) until cooked.
4.Meanwhile, combine yogurt, coriander and the reserved tablespoon of paste in medium bowl. Season to taste.
5.Serve chicken kebabs sprinkled with remaining marjoram. Serve with yogurt and lemon wedges.