Go to www.bing.com/webmaster/tools/content-removal and sign in with your Microsoft account (formerly known as Windows Live ID). In the Content URL input box, enter the exact URL you found in the Bing web results (for example, by using Copy Shortcut/Copy Link Address functionality in your browser)

Visit Bing Webmaster Tools (https://www.bing.com/webmasters) and log in using your Microsoft or Bing account. Add your website to the Webmaster Tools dashboard if you haven't done so already. Select the website you would like to remove the URL from. In the left-hand menu, click on "Configuration" and then "Block URLs."