if your divorce was finalized in a foreign country you will need to send a copy of your divorce decree to the Ontario Registrar office, with a form. The forms you need to fill out and send are for them to investigate whether your marriage was legally dissolved according to Ontario marriage laws, so that you are legally permitted to re-marry.
There's information on their website here
http://www.toronto.ca/registry-services/marriage.htm
You might also need to know that it takes forever and a day for the Province to do just about *anything*. Getting your marriage license after you send in the required forms will take a while, and then once you're married, getting your certificate could take a while as well. If for some reason you need that faster than say, 6 months, you might want to consider getting married elsewhere.
Call them, they can give you more info.