How to Make It
Light a grill or preheat a grill pan. In a large bowl, combine the cumin, garlic and olive oil. Season generously with salt and pepper, then add the lamb and turn to coat. Thread the lamb onto 8 skewers. Let stand for 10 minutes.
Meanwhile, working over a medium bowl, grate the cucumber on the large holes of a box grater, stopping when you get to the seedy center. Stir the yogurt into the grated cucumber. Transfer the mixture to a strainer lined with a coffee filter or paper towel and let drain for 10 minutes. Transfer the cucumber salad to a serving bowl.
Grill the lamb kebabs over moderately high heat until charred and medium rare, about 7 minutes. Let rest for 5 minutes, then serve with the cucumber salad.