Cook the rice in salted water over low heat for 15 minutes.
Lightly fry the mussels in a dry pan.
Wash the cucumber and cut it into cubes.
Wash the lettuce leaves, dry them and put them in salad bowls.
Place the chilled rice on top of the salad and spread it over the salad bowl to make a hollow in the rice. Put the cucumber in the recesses, then the cooled mussels.
Serve the salad with a quarter of a lemon, if desired, season with olive oil. Delicious, satisfying and easy!