What airlines fly to São Miguel and how do I get there from the US or Canada?

Yes. Azores Airlines (SATA) has operated direct flights from North America to Ponta Delgada, São Miguel, with routes from cities such as Boston and Toronto, mainly on a seasonal basis in some cases. Routes and schedules change from year to year, so check the airline's official site before booking. If there is no direct flight on your dates, you can connect through Lisbon or Porto, which have frequent flights to the islands.