Barley Salad With Ham and Black-Eyed Peas

3/4 cup quick-cooking barley

2 cups frozen black-eyed peas

3 tablespoons extra-virgin olive oil

3 tablespoons sherry vinegar or red wine vinegar

2 tablespoons light mayonnaise

Kosher salt and freshly ground pepper

7 ounces mixed baby greens (about 12 cups)

3/4 pound deli ham (preferably low sodium), in 1 piece, chopped

1 1/2 cups cherry tomatoes, halved

5 radishes, chopped

4 scallions, chopped

2 tablespoons chopped dill pickles or cornichons