No. The composite/admin user cannot be disabled/removed in TDV.
1. When you try to remove it from the Web Manager, it will throw the following warning:
"Warning. You are about to delete yourself. You will be logged off as a result. Do you wish to continue?"
2. If you continue, TDV will reject the deletion attempt by throwing the following error message in web manager:
"Service failure: NotAllowed: Cannot destroy user "admin" in domain "composite"