Wash the fresh arugula thoroughly and dry it.
In a large bowl, place the arugula.
Add the halved cherry tomatoes and sliced cucumber.
Add the thinly sliced red onion.
Crumble the feta cheese over the salad.
In a small bowl, whisk together the olive oil and balsamic vinegar.
Drizzle the dressing over the salad.
Toss the salad gently to combine all ingredients.
Season with salt and pepper to taste.
Serve immediately for the freshest taste.