Sadly Dell do not ship Windows Reinstallation DVDs with the systems anymore. I recommend you contact Technical Support as soon as the system arrives and Request a Reinstallation DVD. If you reside in the US or CA you may fill out this Media Request form: www.dell.com/recoverymedia Unfortunately Dell have not extended the courteous of this form to customers in all other regions.  Note Dell Technical Support may tell you to use Dell Backup and Recovery to make installation media but in my experience this is not as reliable a solution as an actual Reinstallation DVD.
When reading the full specs for a Inspiron One 23 in my basket I came across this ...... Shoild the need arise, how do I re-install the Win 8 OS. Thanks.  
No OS Windows® Recovery Media supplied ??