Place salad in a large bowl. Sprinkle with salt.
Toss the salad.
Add vinegar or lemon juice. Add extra-virgin olive oil.
Mix thoroughly. Taste and adjust the ingredients if necessary.
Do not prepare the salad ahead of time, but just before serving. The acidity of the vinegar (or lemon) would spoil the leaves, and after a few minutes, the salad would be ruined.