From a quick test with my laptop, you can remove the Windows Account from your PC account as follows. My files and settings (wallpaper, etc.) remained as they were before switching back to a local account:
Go into Start menu -> Settings, then click "Sign in with a local account instead"
Type your password and click 'Next'.
Leave the username field as is and the password fields blank and click 'Next'.
It will apply the change and sign out. Click the avatar to log back in.
I then tested the Windows Store by picking a free App and installing it. It asked me for my Windows account password and then installed the app. When I rebooted afterwards, it was still set up as a local account, i.e. automatically logged me in and no e-mail address shown while logging in.
Edit: I found something rather interesting - My OneDrive folder still works after switching my laptop back to a local account. The main reason I originally had my laptop configured with a Microsoft account was that OneDrive said I must use a Microsoft account to log in to be able to use OneDrive, yet I now have OneDrive still syncing fine after switching back to a local account. Whoops...