To answer both questions, the quick cheap, environmentally safe way to deal with mosquitos and black files is wind. Just get a desk fan that rotates and setup in front of where you are sitting outside, put it on high and let it blow the bugs away. In areas where the bugs are bad and in the spring grab Muskoil, but get the liquid not the aerosol.
Re Bear spray, it is legal to own, buy and bring into Canada. But its use and possession is controlled. It must be clearly labeled as Bear Spray and contain Capsaicin. In Canada our weapons laws are much more restrictive, so keep in mind the following:
1) declare it when you cross into Canada
2) do not carry on your person in places where bears are not a threat ie the mall
3) do not conceal it when carrying it and identify that you are carrying it when questioned by police or park rangers
4) NEVER use it (even in self defense) against another person (I know that argument again). Canada does not have the same self defense laws and even if the use saves your life you will likely be dealing with an Assault with a Weapon charge (like a Felony up here). That's OK though, there are far more bears then Gang Bangers up here anyway :)