Blanch whole green beans (works best with young tender ones) in a big pot of boiling water until just tender crisp. Drain and cool in icy water. Drain and pat dry with paper towels if need be. Chill in fridge.
Cut some swiss cheese into cubes. Add to beans. Toss beans and cheese in any oil and vinegar based dressing.
Serve immediately as the beans lose their bright colour after being in contact with the vinegar for a while.
This can be a meal or a side salad.