Typical uninstall:

1. From the Finder go to the Applications folder.
2. Look for the Cisco folder and open it
3. Then double click on Uninstall Anyconnect or Uninstall Cisco Secure Client to start the uninstall process
4. Follow instructions to uninstall VPN program

Manual uninstall:

As root, run the following shell script from the Terminal (Go to Application -> Other -> Terminal):

 sudo /opt/cisco/anyconnect/bin/vpn_uninstall.sh

or

 sudo /opt/cisco/secureclient/bin/vpn_uninstall.sh

You will be prompted for your password. Once you enter it, just follow the steps.