A tsatiski style dressing: Fat free natural yoghurt, black pepper, lime juice, cucumber and a hint chili is nice
The SW magaziine tikka sauce is lovely on top of salad too: fat free natural yoghurt, salt, curry powder, garlic, ginger, a tsp of cumin, and a hint of chili - sounds nicer than it sounds i think
If you're in a major rush, or forget to make a dressing like i did yesterday, just squeeze some lemon over the top and some black pepper or chili - it gives the lettuce some flavour!