Heat the oil in a large frying pan and sauté the onion and garlic for 5 minutes until soft. Add the lamb and ½ the dried herbs, and stir-fry for 2 minutes, until warmed through.
Meanwhile, lay the tortillas out on to plates. Divide the salad, tomatoes and cucumber between the wraps and top with the lamb mixture. Sprinkle the remaining dried herbs over the tzatziki and serve on the side.