To make sauce:
Stir together yogurt, cucumber, garlic, lemon juice, dill, salt and pepper in a small bowl. Cover and chill 30 minutes.Advertisement
Wrap pitas in damp paper towel and microwave for 20 seconds. Place puffed-side down on plates. Down the middle of each, evenly layer lettuce, sauce, onion, tomato slices and feta. Fold up both sides like a taco.