The key to this salad is to have everything very cold. It is so refreshing on a summer day.

Core tomatoes and peel if desired; refrigerate on serving platter for at least 1 hour.

Twenty minutes before serving, combine olive oil, ¼ cup ice water, lime juice, and garlic in a covered container and shake briskly; refrigerate. Submerge onion slices in ice water in 1 bowl. Separate lettuce into individual leaves and submerge in ice water in another bowl.

To serve, remove tomatoes and chilled platter from the refrigerator. Lift the lettuce from the ice water, shaking off most of the excess water; layer on the chilled platter. Quickly slice the tomatoes and arrange evenly on the lettuce; lift onion from ice water and scatter over tomatoes. Shake dressing and spoon over tomatoes; season to taste with salt and pepper, and garnish with feta and capers. Serve at once.