Makes 8 sandwiches (4 servings)

Assemble these sandwiches, which are like a hand-held salad, just before serving, because the dressing quickly softens the bread.

For the Lemon Vinaigrette

½ cup extra-virgin olive oil
½ cup fresh lemon juice
2 teaspoons minced fresh oregano or ½ teaspoon dried oregano
2 cloves garlic, minced
½ teaspoon sugar
¼ teaspoon freshly ground pepper, or to taste
1/8 teaspoon salt, or to taste

For the filling

4 cups coarsely shredded stemmed salad spinach leaves or romaine lettuce
2 plum tomatoes (at room temperature), halved lengthwise, each half cut into 1/8-inch-thick slices
½ cucumber, halved lengthwise, each half cut into 1/8-inch-thick slices (about 1 cup)
½ cup crumbled feta cheese (about 2 ounces)
¼ cup coarsely chopped onion
¼ cup pitted and sliced kalamata olives (see Tip)
2 tablespoons coarsely chopped fresh basil leaves
Freshly ground pepper

For the bread

Four 7-inch plain pita bread rounds, each cut to form 2 half-rounds

Whisk together all the vinaigrette ingredients in a small bowl, making certain the sugar is dissolved. Taste and adjust the seasoning.

To make the filling, toss together all of the ingredients (except the pepper) in a medium bowl. Whisk the vinaigrette, add it to the bowl, and toss again. Taste and adjust the seasoning.

To assemble each sandwich, split open and stuff each pita half with about ½ cup of the salad mixture; sprinkle with pepper.