Wash and slice the cucumber into thin rounds.
Halve the cherry tomatoes and thinly slice the red onion.
Add the cucumber, tomatoes, red onion, olives, and crumbled feta cheese to a large serving bowl.
In a small bowl, whisk together the olive oil and fresh lemon juice.
Pour the dressing over the salad.
Gently toss until all the ingredients are evenly coated.
Serve immediately or refrigerate for 15 minutes to allow the flavors to blend.