Slice cucumber in half lengthwise. Slice each half lengthwise into two pieces. Remove seeds (optional) and slice again lengthwise. Cross cut the 8 strips of cucumber into bite-sized pieces about one-half inch in length. Place pieces in mixing bowl.
Slice ends off tomatoes and discard. Dice tomatoes into half-inch pieces. Add to mixing bowl.
Clean seeds and ribs from half of one bell pepper and one small hot pepper. Slice into strips and then into half-inch pieces. Add to mixing bowl.
Dice onion into one-quarter inch pieces and add to mixing bowl.
Drizzle sunflower oil and vinegar over diced vegetables. Stir to coat evenly.
Chop parsley and sprinkle on salad. Season with salt and pepper to taste.
Grate Bulgarian feta cheese over salad and serve.
Notes
You could use a whole bell pepper and omit the hot pepper; or you could omit pepper altogether. A classic Shopska salad can be made from cucumbers, tomatoes and feta alone.