Deleting .dmp files under Windows 8.1

I have several gigabytes of .dmp files that I'd like to delete, because they're clogging up my (rather small) SSD boot drive.

Apparently under Windows 8.1 there is no way to start File Explorer in administrator mode — although you'd think that right clicking on explorer.exe and selecting 'run as administrator' would do the trick — regardless of the fact that the sole account on this machine is an admistrator account. So how do I get rid of uneeded .dmp files?

Alternatively, is there a way to star File Explorer in administrator mode short of downloading third-party utilities or rooting around in the registry, which I'm not willing to do?