Wash the cucumber, tomatoes, bell peppers, and red onion under cool running water. Dice the cucumber and bell peppers into bite-sized pieces, chop the tomatoes into quarters, and slice the red onion thinly. Place all these veggies into a large mixing bowl.

Add Kalamata olives, crumbled feta cheese, chopped fresh parsley, and minced garlic to the bowl. Gently toss to mix all the ingredients evenly.

In a small bowl, whisk together extra-virgin olive oil, red wine vinegar, dried oregano, salt, and black pepper until fully emulsified.

Pour the dressing over the salad and gently toss the mixture again to coat the vegetables evenly.

Cover the salad with plastic wrap and refrigerate for 30 minutes to allow flavors to meld.

After chilling, give the salad another gentle toss. Adjust seasoning if necessary and serve cold.