Spread the mesclun, potatoes and beans on the tortillas, then top with the tuna mixture.

Stir the mayonnaise and then stir in the canned tuna mixture.

Pour just enough of the dressing over the tuna mixture to moisten well.

Using your hands, form the tuna mixture into 6 firm patties.

Place 1/3 cup of the tuna mixture inside.

Fold the tuna mixture into the mayonnaise and blend well.

Fold in tuna mixture, adding the reserved cooking water if needed to thin sauce.

Add tuna mixture, and toss gently to mix.

A quibble: This tuna mixture, presumably chopped early in the evening rather than to order, is sometimes strong tasting.

Top with tuna mixture and remaining bread.