Cut the green lettuce leaves into small pieces and put them on a flat dish. You can use the upper part of the leaves of Peking cabbage. Cut the tomatoes into large slices and put them on the salad.
Cut the cucumber into half rings 0.5 cm thick, put it on top of the tomatoes. Add salt and pepper with a mixture of freshly ground pepper to taste.
Remove the tuna meat from the brine, divide it into small pieces with a fork and put it on the vegetables.
