Step 1

If using Aleppo pepper, place in large bowl and mix in 1 tablespoon warm water. Let stand until thick paste forms, about 5 minutes. If using dried crushed red pepper and paprika combination, place in large bowl and stir in 2 tablespoons warm water and let stand until paste forms, about 5 minutes. Add yogurt, olive oil, red wine vinegar, tomato paste, 2 teaspoons coarse salt, and 1 teaspoon black pepper to spice mixture in bowl; whisk to blend. Stir in garlic and lemon slices, then chicken. Cover and chill at least 1 hour. Do ahead Can be made 1 day ahead. Keep chilled.

Step 2

Prepare barbecue (medium-high heat). Thread chicken pieces on metal skewers, dividing equally. Discard marinade in bowl. Sprinkle each skewer with salt, pepper, and additional Aleppo pepper or paprika. Brush grill rack with oil. Grill chicken until golden brown and cooked through, turning skewers occasionally, 10 to 12 minutes total. Transfer skewers to platter. Surround with lemon wedges and serve.

Step 3

*A slightly sweet Syrian pepper with a moderate heat level; available at some specialty foods stores and from wholespice.com.

Step 4

**A thick yogurt; sold at some supermarkets and at specialty foods stores (such as Trader Joe's and Whole Foods markets) and Greek markets. If unavailable, place regular yogurt in cheesecloth-lined strainer set over large bowl. Cover and chill overnight to drain.

Step 5

Aleppo pepper is sold finely ground or crushed into small flakes; either one will work well in this recipe.