What is the process for requesting flight following in Canada?
The general procedure in Canada is the same as in the USA: to contact the nearest ATC unit and ask for a radar service.

For any VFR flight beyond 25nm from the point of departure it is mandatory in Canada to file either a flight plan or a flight itinerary before departure - (CAR602.73(2)).

The provision of radar service to VFR traffic is typically at the controller's discretion and dependent on workload. 

VFR Traffic in the Montreal area is generally expected to follow the suggestion published in the Canada Flight Supplement to contact the Montreal ACC 30 minutes prior to departure to obtain a discreet squawk code. This procedure becomes mandatory if you hope to penetrate the Class C airspace.

Generally it's worth reading the appropriate national publications and/or getting advice from an FBO at your point of departure when flying in a foreign country (Canada).