This link is the location - where you are on the website - and to remove it open skin1/customer/home.tpl, find
Code:
{if $usertype eq "C"}
{if !%position.first%}
<div id="locationbar">
{include file="location.tpl"}
</div>
{/if}
{/if}
and comment it out (surround the code with {* code here *}. Your code may look a little different but you get the idea
As for the Webmaster mode that is the one. You can use Firebug in Firefox and is very helpful but won't tell you which template as it look at the site and not the code.