Tina-
Couple of things. Lets make sure you understand what "canonicalization" is......when the search engines determine the best version of a single page that can be pulled up using more than one URL. In the process different URL's would be able to display the same identical content.
This could be happening for a number of reasons and might not make a big difference in your SEO or it could be hurting your SERP values. Essentially you want to make sure that your rel=canonical issues are simple redirects that are necessary so that you aren't being penalized for duplicate content. To make sure this is correct work through the errors and make sure that your sitemap is set up correctly and you are effectively using your url descriptions to tell the search engines what the various pages contain. It does make sense to make sure that your URL is as descriptive as possible.
If you want to get the simplest and easiest explanation of rel=canonical issues, read Matt Cutts blog posting from a few years back. We use it in our SEO playbook. http://www.mattcutts.com/blog/canonical-link-tag/
I would recommend 2 plugins for you with wordpress (I have done over 30 wordpress sites in the last 6 months and we havetested a bunch of them).
Wordpress SEO by Yoast. This is an all in one SEO plugin which will solve your "description tag" issue and will give you much more flexibility for basic and advanced SEO. Here is the link: http://yoast.com/wordpress/seo/#utm_source=wpadmin&utm_medium=plugin&utm_campaign=wpseoplugin
There is another plugin called redirection by John Godly. It manages your 301 redirects and keeps track of your 404 errors (rel+canonicals) and helps you clean up your site. It is solid and easy to use.
Another issue you might be having with your duplicate content can be avoided by creating original content., if you have one page with a widget and another with a blue widget and another with a pink widget and all the verbiage is the same, except for the color, then you have duplicate content. Use the rel=canonical to make sure you don't get penalized for duplicate content. Another solution is if on the widget pages you can provide several different descriptions of the widgets that go beyond colors, then you start to create unique content and you get SEO value for each separate widget page without having to do a rel=canonical. We have several ecommerce clients that have 10-15 variations of the same product and we have helped them develop unique content for each one, (hundreds of extra pages of content), which has dramatically increased their relevancy and quality score for their specific keywords....but it has to be unique.
Your last issue is related to Canada and search results. This really relates back to your internal sitemap structure. Remember, Google and other search engines send spiders to your site to crawl. They only know what they can see and what you tell them. if you dont do a good job of sitemap/url structure and definition, they are going to try and figure it out themselves. If I was you, I would create a separate url structure for your canadian group that would be something like....www.dropshippingsupplies.com/specifickeywords_canada_locations Then all of the SEO value stays with your core site but you designate that those pages and keyword content are related to Canada. You should also make sure that you have geotargeted keywords in the core content of the page....so that you mention canada or the cities and towns where you aretargeting, within that core content.
Hope this helps..
Mark