Make a deep cut along the back of each shrimp. Remove the dark intestinal vein, then set them aside.
Rinse, dry, and trim the green onions and slice them diagonally; peel and grate the ginger; peel and crush the garlic; rinse, halve, deseed, and slice the chili. Put them all into a bowl and set aside.
Peel the mangoes, then remove the ﬂesh from the stones and cut it into 1⁄4 in. (5mm) thick slices.
Mix the tomato purée, soy sauce, sherry, and sesame oil in a small bowl.
Rinse and dry the lettuce leaves and arrange them on individual serving plates. Set aside.
Heat the peanut oil in a wok or large frying pan. Add the green onion mixture and stir-fry for 1 minute. Add the shrimps and continue stir-frying until they are just beginning to turn pink. Add the mango slices and stir-fry until the shrimps turn completely pink and unfold, and the mango is heated through. Divide mixture among the serving plates.
Add the soy sauce mixture to the wok and bring it to the boil. Season to taste, then spoon over the shrimps with chili and mangoes and serve.
Per serving: calories 198, carbohydrate 21 g (including sugar 20 g), protein 13 g, fat 7 g (saturated fat 1 g) Good source of vitamins A, B group, C, and E.