Grilled Lamb Stuffed Pitas with Yogurt Sauce

Ingredients

• 1 cup plain Greek yogurt
• ½ cup minced fresh mint
• 2 tablespoons lemon juice
• 2 tablespoons tahini
• 2 tablespoons extra-virgin olive oil
• ½ teaspoon salt
• 1 onion, cut into 1-inch pieces
• 1 cup fresh cilantro leaves
• ¼ cup extra-virgin olive oil
• 1 tablespoon grated lemon zest plus 3 tablespoons juice
• 1 tablespoon ground coriander
• 1 tablespoon ground cumin
• 1 tablespoon paprika
• 2 teaspoons salt
• 1 ½ teaspoons pepper
• ½ teaspoon cayenne pepper
• ¼ teaspoon ground cinnamon
• 2 pounds ground lamb
• 4 (8-inch) pita breads