As JDFan stated, you can also remove your password. You would just need to hit ENTER when the password box shows up. TweakUI can bypass this automatically since it will know which account to auto login as.
Personally, I don't recommend either option as it's a security risk. Why have a password if you are going to bypass it?Perhaps if it were a standard user account, but an admin account should definately have a password and no auto login.