Peel the cucumbers and dice them. Wash and dice the tomatoes. Wash the peppers and cut into small pieces. Finely chop the mint and parsley. Peel the onion and chop finely. Wash the lettuce, drain and cut into small pieces. Put the salad with the vegetables in a bowl. Squeeze the lemon and add it with the oil and herbs. Mix everything well and season with salt and pepper.