Halve the cherry tomatoes and place in a bowl with a little salt and a drizzle of olive oil. Leave for up to 30 minutes.
Halve the cucumber lengthways, then scrape out the seeds with a teaspoon. Slice the halves into half-moons, then place in a colander, sprinkle with a little salt and leave to drain for 30 minutes.
When the tomatoes and cucumber are ready, combine them in a large salad bowl with the olives and crumble in the feta cheese. In a separate bowl, whisk together the vinegar and a little seasoning and the oregano. Then whisk in enough extra virgin olive oil to make a thickened emulsion.
Drizzle the dressing over the salad vegetables and toss thoroughly before serving.