In a bowl, combine the drained tuna, mixed salad greens, sliced cucumber, cherry tomatoes, sliced red onion, and sliced black olives. Toss gently to mix all the ingredients together.

In a small bowl, whisk together the extra-virgin olive oil, red wine vinegar, Dijon mustard, salt, and pepper to make the vinaigrette dressing.

Drizzle the vinaigrette over the tuna salad and toss to coat everything evenly.

Divide the Tuna Salad with Mixed Greens into individual serving bowls or plates.

Optional: Sprinkle with grated Parmesan cheese and fresh herbs for added flavor and presentation.

Serve the salad immediately and enjoy!