American citizens are required to file taxes from abroad and to declare all world income.
Is something like this also a requirement of Canadians when not residing in Canada? Does anyone have any information on this subject?
No — the U.S. is the only country that imposes such a requirement on its citizens. Eritrea is another country (the only other...) in the world which taxes non-resident citizens, but it is not a regular income tax.
Every other country in the world taxes by residency and not by citizenship.
Canadian citizens who no longer reside in Canada (i.e.: have permanently emigrated, can prove that they did, and are officially residents elsewhere) are only taxed on income from Canadian sources.
For more information see Canada Revenue Agency: Non-residents of Canada.