1. Preheat gas grill to medium. In a large bowl, combine pork, coriander, cumin, cinnamon, nutmeg, egg, onion, parsley, 1 clove garlic and 1 tsp. salt. Mix thoroughly with your hands. Form mixture into 1 1/2-inch balls, then press into football shapes.
2. Oil grill grates. Grill patties, turning once, until cooked through, 8 to 10 minutes total.
3. In a small bowl, combine yogurt, lemon juice, 1/2 tsp. salt and remaining garlic. Divide salad greens among 4 serving plates. Top with patties and drizzle with yogurt sauce. Serve immediately.