You can't. The vendor can cloak it (quite easily) but most of them don't. Why? Because it's a simple thing like providing a landing page with a couple of lines of php which direct you to a new landing page. Unfortunately, that means that the 'original' landing page gets blown out by Google etc.

They could get round it by having their original landing page as, say, index.html and a specific landing page for affiliates as index1.php. All the index1 page does is redirect to index.html. That drops the 'hop'. As the 'hop' doesn't matter anyway to either vendor or affiliate the only reason I've ever heard for it to be shown is that affiliates like to see it to make sure the system is working properly and their commission isn't going to get stolen. Which is crap because CB stores the last link and uses it when the buyer buys.

Ask the vendor to cloak. I've done it with a few vendors - and, by and large, they've done it. The ones that didn't - I dropped.