Some good summer lunch dishes, all with lots of recipes ready to google:
Gazpacho -- the basic red version is tomatoes, cucumber, green pepper, onion, bread or bread crumbs, vinegar (I prefer lemon juice) & a splash of olive oil. There are many other varieties out there, including green & white ones (involving almonds, grapes & other good non-dairy stuff).
Panzanella - Italian bread salad, basic ingredients are dry bread, ripe tomato, oil & vinegar (I prefer lemon juice), plus other veg & herbs to taste.
Fattoush - Middle eastern salad -- dried pita, chopped tomato, cucumber, peppers, lettuce, lots of parsley, lots of mint, lemon juice/olive oil/garlic dressing
Salade Nicoise - hard boiled egg, tuna, olives, lettuce, often green beans & boiled potato, dressed with oil (usually with a vinaigrette). If you put it inside a crusty bread loaf & press it overnight, the sandwich is called Pan Bagnat & it's really good too.
One of my favorite salad meals is: lettuce, shredded carrots, corn, artichoke hearts, oil-packed tuna & croutons, dressed with a lemon-juice vinaigrette.