Place the yogurt, lemon juice and zest, ginger, paprika, cumin, salt, pepper, coriander, and cayenne in a large mixing bowl and stir to combine, or place them in a food processor and blend to puree. Add the lamb cubes and toss to coat well. Cover and refrigerate for 6 to 24 hours.
Soak about 20 6-inch wooden skewers, or 10 12-inch skewers, in water to cover for 30 minutes. You can also use metal skewers, which do not need soaking.
Thread the skewers with the lamb. Discard the remaining marinade.
Heat an outdoor grill to high, or heat a grill pan or a heavy skillet over medium-high heat. Grill the kebabs 4 inches from the heat source, for about 8 minutes total for medium rare, turning them every few minutes to get nice grill marks on most sides of the meat.
Serve hot or at room temperature with the cilantro, lemon wedges and chutney, if desired.
Notes
Here I opted to cook the lamb on its own, rather than alternate it with vegetables on the skewers. This was so I could totally focus on the best cooking times and doneness for the meat, without worrying about vegetables becoming overcooked, or vegetables not being tender enough when the lamb is perfect.
Consider making separate vegetable kebabs and letting everyone pull the different elements of the meal together on their own plates.
If you want to add vegetables to these kebabs, consider the optimal cooking time for the lamb (depending on how rare or not you like your lamb), and pick vegetables with similar cooking times (see Veggie Kebabs).
Cut this recipe in half for 1 pound of lamb meat if you have a smaller group.