Any shipment of corals (e.g. zoas) across an international border is covered under the CITES treaty. Basically, it can't be done unless you get a very expensive permit and even then, you run the risk of lengthy delays in customs. I know of no US based lifestock store which will ship stock to Canada.
In Canada, there is a frag exchange group called 'frags.ca'. They often have zoas for sale, as well as many other types of corals. You can also look for other local hobbyists in your area (try the Canadian discussion forum: aquaria.com) or commerical groups such as J&L (jlaquatics.com).