Peel the cucumbers and chop them in big cubes. Cut the peppers lengthwise in two, take out the tops, clean the seeds and chop finely. Peel the onion and chop it in rings. Chop feta cheese and tomatoes in cubes. Put tomatoes, cucumbers, peppers and onion rings in a deep bowl. Add finely chopped parsley and mint and salt. Pour some olive oil on. Add cheese and olives. Put half a lemon juice on and serve.