Chop all the vegetables and put them in a big bowl. Cut the tomatoes into bite-size chunks - I like to use big heirloom tomatoes. Peel the cucumbers and slice in half lengthways. Using a teaspoon, scrape the seeds of the cucumber out, starting from the top and pulling the spoon to the bottom. Then slice the cucumber into semi-circles. Deseed the green capsicum and cut into thin strips. Slice the red onion in half and then into thin semi-circles, and soak them in a small dish with the red wine vinegar for a few minutes then add it all to the bowl. Add the other ingredients except the feta, season with salt and more olive oil if needed and toss gently. Put the feta on top in one big flat chunk. Serve as a side or on its own. When serving, take a Small chunk of feta to eat with the salad. Don't be shy with the olive oil, but it'll taste better if you use a good-quality one.