The Edge cache files for a specific Windows user are
%homedrive%\Users\ **{user} \AppData\Local\Microsoft\Edge\ {profile} \Cache\Cache_Data\* **
Kill any running msedge.exe task before trying to remove the cache files. Because there's no way of knowing what a particular user's profile directories are called, you'd probably have to loop through each folder in User Data looking for folders containing a Cache_Data folder in order to DEL it or its contents. You could also query the registry to find them:
reg query HKEY_CURRENT_USER\Software\Microsoft\Edge\Profiles /s /f Path