Rinse the shrimp in cold water and cook in salted water. Wash the lettuce leaf and place it on a paper towel to drain all the water. Open the can of corn and pour into a separate bowl. Squeeze the lemon juice and strain it through a sieve. Open the can of tuna and pour out any excess liquid.
Peel the shells from the shrimp so that only the meat remains and place them in a separate container. Place coarsely chopped lettuce and canned corn into a salad serving bowl. Cut the cucumber into thin slices and also add to the salad.
Mash the tuna with a fork and send it there. Also pour in the juice of one lemon and mix everything well. Add some of the peeled shrimp, salt, pepper and oil and mix everything well so that everything is evenly distributed throughout the salad. Place the salad on a serving plate and garnish with the remaining shrimp.
Serve the salad in a large deep dish so that everyone can help themselves as much as they prefer, or take individual serving plates. To make it more impressive, purchase round or rectangular plates. Garnish the salad with finely chopped herbs. If desired, serve a separate container for fresh rye bread.