Start by washing the cucumber, tomato, and onion thoroughly. Slice the cucumber into thin rounds, chop the tomato into bite-sized chunks, and finely slice the red onion. Arrange all prepared vegetables in a large mixing bowl.
Add the chopped coriander over the vegetables, distributing evenly for fresh aroma and flavor.
In a small bowl or jar, whisk together the olive oil and freshly squeezed lemon juice until well combined. Season with a pinch of salt and black pepper.
1 large cucumber
Pour the citrus dressing over the vegetables in the large bowl. Gently toss everything together until all ingredients are evenly coated and the salad glistens with the fresh dressing.
Adjust the seasoning with additional salt or pepper if desired. Give a final gentle toss to combine everything well.
Serve immediately for maximum crunch and freshness, or refrigerate for up to an hour before serving to let the flavors meld beautifully.