remote install OS X on Mac Mini (sans disk drive)

I wanted to sell my Mac Mini so I went through the process of deleting the harddrive using that command-r screen on load up. But I completely forgot about re-installing the operating system. So now I get the blinking folder icon when it boots.

How do I re-install OS X? Is there a way to remote install it? I can't seem to find any information online.

My Mac Mini is a 2.3GHz Intel Core i5, 2GB RAM, 500 GB HD. It lacks the DVD drive so that option is not available.

Thanks.