I haven't checked on my Win10 system at home, but I would imagine it's a matter of opening up the actual control panel (NOT the settings which is a rather truncated version of it) and the 'User Accounts' should still be there. Basically you'll:
In the Win10 search bar, type 'Control Panel', click the control panel when it comes up.
Go to 'User Accounts'
Go to 'Manage Another Account' (this pulls up all the accounts)
Click the one to 'manage'.
One of the options will come up 'delete this account', delete it.
It will ask to verify if you want to just remove access, or delete all files. Choose which option you want.