Ingredients

• 1/4  cup  finely chopped red onion
• 1  teaspoon  dried oregano
• 1  teaspoon  grated lemon rind
• 1/2  teaspoon  salt
• 1/4  teaspoon  freshly ground black pepper
• 1  pound  ground turkey
• 6  tablespoons  (1 1/2 ounces) crumbled feta cheese
• Cooking spray
• 1/4  cup  grated English cucumber
• 1/4  cup  plain fat-free yogurt
• 1  tablespoon  chopped fresh mint
• 4  (1/4-inch-thick) slices tomato
• 4  green leaf lettuce leaves
• 4  (2-ounce) Kaiser rolls or hamburger buns