Well, there are many many foreigners in Canada, as you probably already know.
If you have a Permanent Resident Status or an Open Work Permit it should not be that hard, as long as you can speak English or French (please keep in mind that certain areas basically speak one or the other language).
If you have basic education (like high school only) chances are you will find a job in retail or restaurants.
Now, if you have more education you will probably get some higher paying job, however you will need to get your certifications accessed and validated.
But, if you are in the country as a tourist do not even think about working illegally...no one will give you a job. If they do you can get in trouble, so do not even consider that.