2 tsp. fresh lemon juice
2 tsp. red-wine vinegar
2 Tbs. extra-virgin olive oil
1/4 tsp. dried oregano, crushed
Kosher salt and freshly ground black pepper
1 large ripe tomato (about 9 oz.), cut into chunks
1/2 cucumber, peeled and cut into large dice
1/4 medium red onion, thinly sliced
8 to 10 large leaves from a heart of romaine lettuce
16 to 20 large mint leaves (from about 4 sprigs)
5 oz. feta cheese, cut into 3/4- to 1-inch cubes
3 oz. black olives, such as kalamata (about 1/2 cup)
In a small bowl, whisk the lemon juice, vinegar, olive oil, and oregano with a fork; season with salt and pepper. Put the tomato, cucumber, and red onion in a salad bowl. Sprinkle lightly with salt (about 1/4 tsp.). Give the vinaigrette a whisk, pour about 1 Tbs. of it over the vegetables, and toss lightly.
Wash and dry the lettuce. Trim the tops of the leaves if they’re bruised or browned, cut the leaves lengthwise into 3 strips, and then across into large squares. Wash and dry the mint and cut crosswise into thin strips (you should have about 1/4 cup, loosely packed). Add the lettuce to the salad bowl. Add one cube of feta to the remaining vinaigrette and mash with a fork. Pour over the lettuce and vegetables and toss. Add the remaining feta and the olives and sprinkle on the mint. Toss gently and serve right away.