There is no legal way to do this. Any installation of OS-X on non-Apple hardware is a violation of the Apple license agreement -- and discussion of violating license agreements here is also a violation of the terms of service of the Dell forums -- which can get you a warning (or banned).
oh, ok thanks for letting me know. I saw that apple offer a way to install windows on macs so I thought it may be possible the other way around too!
Do you know if its possible to easily install other operating systems on the XPS?
The license agreement from Apple requires the Apple ROMs be present - which they are only on Apple hardware.
You can likely install any OS you'd like on the system subject to there being drivers available -- though on Skylake hardware like this one, running anything older than Windows 8 requires a non-trivial process.