They are stored in this directory (and you can delete them):
%ProgramData%\Cisco\Cisco Secure Client\VPN\Profile
Pro tip for a long standing bug - when ever you upload the profile to the dashboard, the dashboard ALWAYS appends .xml onto the filename, even if the filename already ends in .xml. So if you upload profile.xml, it gets saved as profile.xml.xml, and download to the client like that. So you need to upload profile.xml as profile.