Well, if you are just wanting to display a page, you can either do a re-direct (as has already been shown) or you can read and print the existing page through your script. From a performance standpoint the re-direct is going to be much better for you.
As for the margins question, the print format is as far as I know pretty much entirely up to the browser in question. If you need that much control over how it renders, you might consider putting it into pdf format (for which there are a number of modules in CPAN).