Wash and dry all vegetables thoroughly to remove any dirt. Use a salad spinner or a clean kitchen towel.

Finely chop the romaine lettuce and cucumber, then dice the tomatoes, red onion, and bell pepper into small pieces.

Finely chop fresh parsley, picking only the leaves and discarding the stems.

In a small bowl, combine olive oil, red wine vinegar, Dijon mustard, and minced garlic. Whisk until emulsified.

In a large bowl, combine chopped vegetables, parsley, and grated Parmesan cheese. Toss gently to coat.

Drizzle vinaigrette over the salad and toss quickly to combine before serving.

Plate the salad immediately and serve while fresh and crisp.