Combine cucumber, tomatoes, red onion, olives, and feta in a large bowl.In a small bowl, whisk together olive oil, red wine vinegar, oregano, Dijon mustard, salt, and pepper.Pour the dressing over the vegetables and gently toss.Refrigerate for 10–15 minutes to allow the flavors to blend.Garnish with fresh parsley and serve!*O’ So Good Tip: Use a premium extra virgin olive oil with your red wine vinegar for a bright, fresh Mediterranean flavor!