Slash the chicken pieces a few times to reduce cooking time and allow the flavor to penetrate.
Heat your barbecue to medium. In a pestle and mortar, grind the onion and garlic with the ginger and fresh coriander; add the yogurt and remove to a bowl big enough to marinade all of the chicken pieces. Add the spices, maple syrup and vinegar and mix well. Season the marinade with salt, and then drop in the chicken pieces. Mix them around in the marinade and rub the yogurt mixture into the flesh with your hands.
After marinating for at least half an hour, put the chicken pieces onto the hottest part of the grill. Turn each piece once until it is satisfyingly browned and looking delicious, then move them to a cooler part of the grill to cook gently, turning every few minutes, for about 15 minutes. Cut into the meat to check it is done. It should not be at all bloody, though remember that chicken legs do stay a little red in color even when they've been fully cooked. Serve with some fresh leaf salad and raw vegetables.