You can promote cpa offers the same way you would promote a clickbank offer for the most part. You need to make sure that the offer you are promoting doesn't have any restrictions on it like: search only, or email only.
If you've got no restrictions, then you can either do a redirect (which Ezine Articles is starting to frown on) or point your visitor to a landing page just as you would with a Click Bank product.
Your second question you kind of already answered. Yes, you want to use them to not only attract users to your landing page, but also it gives you a nice
PR (page rank) backlink to your site. It also gives you an opportunity to take over 2 slots on the front page of google (your article and your landing page) if you do some proper
seo.