1. In the bottom of a salad bowl, mix lemon juice, soy sauce, and pepper.
2. Peel and finely chop fresh ginger.
3. Add it to the sauce.
4. Peel the mango and avocado.
5. Cut both into 1-centimeter cubes.
6. Add the shrimp to the mixture, as well as the avocado and mango cubes.
7. Top with lamb's lettuce.
8. You can keep a few mango and avocado cubes, and a few shrimp for decoration.
9. Serve very chilled.