Colin Lynch and Heather Kennaway Lynch have quickly established their seafood-centric restaurant as one of the city’s most sophisticated Italian spots. That reputation owes a big debt to chef Lynch’s crudos, combining subtle knife work, judicious marination and precise temperature control, as in dishes like shima aji (striped jack) exquisitely attired in understated accents of horseradish, chive and caviar. At a time when everybody and their brother is doing crudos, Bar Mezzana laps the field.