In a small bowl, whisk together the olive oil, red wine vinegar, garlic, oregano, Dijon mustard, sea salt, and black pepper until well combined.
Arrange the cucumber, green bell pepper, cherry tomatoes, feta cheese, red onion, and Kalamata olives on a large serving platter or in a large bowl.
Drizzle the dressing evenly over the vegetables and cheese.
Gently toss the Greek Salad to coat the ingredients without breaking the feta.
Sprinkle with additional dried oregano.
Scatter fresh mint leaves over the top.
Taste and adjust seasoning if needed. Serve immediately and enjoy.