not sure, but i think this video may shed some light on what's going on?  apparently, you need to disable secure boot before attempting to boot off the restore disk...
I have a Dell XPS 13 bought this year. I am interested in installing Ubuntu (either the Sputnik image or 12.04 vanilla). I am trying to work out how I could restore to the original Windows 8 image. I have created a restore USB disk but I can't find useful information on how to use the restore disk. How can I boot to the disk so that it can restore my system? I would also like to keep my recovery partitions and restore from the partitions. Is this possible? I have tried to access the recovery programs from boot up but cannot find any restore options. System recovery without using Windows on the Dell XPS 13 seems to be an undocumented feature - can anyone help me? (Otherwise I have am very happy with the machine.)
Using system restore on a Dell XPS 13