To make tostada,cut each tortilla into four 6cm rounds,deep-fry in 180C oil until crisp (about 1 minute per side) and drain on paper towel.
Mix together lime juice,olive oil,red onion,tomato,cucumber,salt and habanero (to taste),adjust seasoning and refrigerate.
To serve,place slices of kingfish with salsa on tostada and garnish with coriander.
Pair with Neil Perry'scalamari tostadas and serve as part of his Mexican banquet (recipes here).