I would not suggest canonicalization of your URLs. Though search engines will treat this better than no action at all (i.e., duplicate content), it will not transfer your "link juice" and all your SEO signals. Supposedly, a meta refresh tag will be treated by search engines just like a 301 redirect via htaccess.
They are real easy to do in Blogger.
Open the template, click Edit HTML then click Proceed. Find the line that says:
<b:include data='blog' name='all-head-content'/>
Right underneath that, add the following:
<meta content="0;url=http://YOUR NEW URL HERE" http-equiv="refresh"/>
Enter your url where it says "YOUR NEW URL HERE." This will be better for SEO purposes than mere canonical URLs (though it isn't AS good as a permanent redirect via the .htaccess file).