This will work in windows 10 1809:
get-appxpackage *pattern* | remove-appxpackage -AllUsers
or
remove-appxpackage -AllUsers -Package somepackagefullname
This is currently not working:
remove-appxpackage -User somesid -Package somepackagefullname
Piping anything to remove-appxpackage with no options will only remove the packages of the current user. EDIT: actually I think this will take care of current users but not new users.