Preheat oven to 300 degrees. Place pitas on a baking sheet and heat for 5 minutes until softened. Heat chicken or other leftover meat and in a microwave or skillet. Combine yogurt, garlic, cucumber, salt, pepper and a dash of Tabasco. Open pita pockets and fill with chicken, lettuce and onion slices. Top with yogurt dressing and extra Tabasco, if desired.