1 hothouse cucumber, unpeeled, seeded, and sliced 1/4-inch thick
1 red bell pepper, large-diced
1 yellow bell pepper, large-diced
1 pint cherry or grape tomatoes, halved
½ red onion, sliced in half-rounds
½ pound feta cheese, 1/2-inch diced (not crumbled)
½ cup calamata olives, pitted
For the vinaigrette:
2 cloves garlic, minced
1 teaspoon dried oregano
½ teaspoon Dijon mustard
¼ cup good red wine vinegar
1 teaspoon kosher salt
½ teaspoon freshly ground black pepper
½ cup good olive oil