Yogurt-Marinated Chicken Kebabs with Aleppo Pepper

INGREDIENTS

• 3 tablespoons extra-virgin olive oil
• 2 tablespoons tomato paste
• 2 1/4 pounds skinless boneless chicken (thighs and/or breast halves), cut into 1 1/4-inch cubes
• 2 tablespoons red wine vinegar
• 1 1/2 tablespoons Aleppo pepper* or 2 teaspoons dried crushed red pepper plus 2 teaspoons Hungarian sweet paprika, plus additional Aleppo pepper or paprika for sprinkling
• 2 unpeeled lemons; 1 thinly sliced into rounds, 1 cut into wedges for serving
• 1 teaspoon freshly ground black pepper
• 1 cup plain whole-milk Greek-style yogurt** (8 ounces)
• 2 teaspoons coarse kosher salt
• 6 garlic cloves, peeled, flattened