1. Combine sumac, cumin, coriander, and Aleppo pepper. In a large bowl, combine 1/4 cup mixture, lamb, onion, garlic, cilantro, chile, and 2 tablespoons salt; thoroughly incorporate with your hands. Refrigerate, covered, at least 3 hours and up to 1 day.

2. Herbed Yogurt: Stir parsley and dill into yogurt. Add lime zest and juice; season with salt. (Can be made-ahead and refrigerated in an airtight container up to 3 days.)

3. Preheat a grill to medium-high. Working with about 1/3 cup at a time, form mixture into roughly 3-inch ovals; thread onto skewers. (You should have about 16 kebabs.) Transfer to a tray lightly coated with oil; turn kebabs to lightly coat all sides. Grill, turning occasionally, until charred in spots and a thermometer inserted in thickest parts reaches 140 degrees, 10 to 12 minutes. Dust with remaining spice mixture. Drizzle Herbed Yogurt with olive oil and serve with the kebabs.