Change View Mode on Taxonomy Tag Pages I have a field that is linked to a taxonomy vocab called tags when creating my "Article" content. When I show these tags on the node page, it links to: /tags/ 

I can't seem to find where I can change the view mode for this /tags/ page. Currently its on teaser view mode.
It is not clear what you want to achieve here but I'm making a guess that you want to display the full content. You can either change the "Teaser" display mode for the content type "article" or you can create a template file "taxonomy-term--tags.tpl.php" and customize it.