Can you legally shoot someone on your property in Ontario Canada?

Even in most of the US, you can't use lethal force against someone for them simply being on your property - it's almost certain to be even more strict in Canada. On matter such as this, you shouldn't trust an answer on which you could make a decision for which you could lose your freedom for being wrong to a website which anyone can answer with no guarantee of accuracy in their answers. Regarding Ontario's laws of lethal force, I would recommend you consult either a lawyer, or the OPD.