A couple of locals, and some stories
Compared to other Italian cities, Venice produced very few home-grown saints. The first was St Peter Orseolo, who fought pirates in the Adriatic and then took part in the revolt against the Doge Pietro IV Candiano, which saw the murder of the Doge and Venice nearly burned to the ground. Peter was elected as Candiano's successor from 976-78 before apparently being overcome by remorse and slipping off without a forwarding address, to live a humble ascetic's life in the monastery of St Michel de Cuxa in the Catalan Pyrenees. One other patrician made sainthood, St Lorenzo Giustiniani as have several former Patriarchs of Venice, including Pius X and John XXIII (although neither were native Venetians).
The low count might have something to do with the fact that Venice constantly challenged and defied papal authority (the animosity was mutual: Pius II called the Venetians 'hypocrites' and that they 'never think of God and, except for the state, which they regard as a deity, they hold nothing sacred'). The people themselves tended to be far more superstitious than pious. Back in the days when the bits of dead saints were considered the best insurance against calamity, Venetians were notorious for swiping bits and bobs if not whole holy bodies from other people's churches whenever possible.
The Venetian calendar has, in addition to all the Roman Catholic saints, an additional 40 saints from the Old Testament, a reminder of the city's early days under the sway of the Byzantines. Altogether, they probably have more saints than any place in western Christendom.