I would like to know how to access a list of sites with the ListData.svc REST API.
The REST interface uses flexible URL conventions for querying data, which enable you to filter, sort and select information from SharePoint Foundation lists directly from the browser.
The ListData.svc is for getting information from lists and libaries not for getting a list of sites.
Link to MSDN
Webs will get you all the sites directly beneath the site, but not their children according to MSDN