The use of the German ID Card is comparable to the use of a driver's license in Canada. In Germany, driver's licenses are used exclusively as a permit to drive a vehicle and cannot be used as an official government issued ID. For these purposes, i.e. to prove their identity and place of residence in Germany, German citizens are issued an official ID Card (“Personalausweis”).
German citizens living outside of Germany do not have to be in posession of a valid ID Card. However, if you live in Canada and wish to apply for one (maybe because you travel to Germany/Europe regularly), you can do so at the German Consulate General in Toronto.
If you still have a registered residence in Germany, you will have to apply for your ID Card at your local municipality in Germany.
More Information on how to apply for a German ID Card can be found here (in German language only): Personalausweis