Hi Cylo, I'm not sure if saying Google caches dynamic pages automatically is an accurate thing to say. I would say it like this: Google is more apt to cache and index a dynamic page if it is given a SEO-friendly URL. Perhaps a Mozzer who is more technically adept than I can comment on the accuracy of that statement.
That being said I definitely wouldn't recommend using dynamic URLs (which it sounds like you are not). Here is how you can set up URL-rewrites in your .htaccess file if you are on a Linux server: http://www.webconfs.com/dynamic-urls-vs-static-urls-article-3.php
Not sure if that's helpful at all. I hope it is somewhat
Dana