Bing Webmaster Center explained that while requesting for URL removals from Bing Search (Live Search) index, pick one from the followings requirements:

.…then login in to your Webmaster account and use any of the following request: -Remove my content remove the URL from Bing search index, takes between 48 and 72 hours. Or -Cache removal will only remove the cached page but not the actual URL from the index.

When entering your information in the support request form, you’ve two choices for either option: “enter single URLs line by line”, or “use a wildcard after the domain name, such as example.com/* or example.com/directory/*”