What kind of job... A waiter? Bartender? Very easy to find jobs as waiters. But u get minimum wage plus tips. Great if you work in a high end restaurant or very busy one. You need a work visa though, and there is no restaurant that will pay for your visa in order for you to come and be a waiter....it is easy to find people here to fill that job so they won't spend resources on a foreigner.
But if you're a trained chef for example, you might have to upgrade here and then look for work after that. If you have lots of experience then someone may hire you outright, but again, they won't be paying for your visa....it is a long process and they can just as easily find locals to fill the position.
If you just wanted to move to Canada, then you wild have to apply on your own, them move here and find a job afterwards, but that is a 2 year process, p,us you would want to bring your wife and child.
It isn't easy, but long term you would have more stability and security for your young family, than perhaps what you have in SA at the moment. Lots to think about but weigh your options carefully!