As many people have found out, Bing is one of the few search engines that gives you the ability to search by Emoji characters. But to get a greater amount of searchers using the emoji search, being appears to be testing a virtual Emoji keyboard.
Rubén Gómez was one of the ones to discover this test, and documented how to force your browser to trigger the virtual keyboard. He even included a video of this feature in action.
Here is a screenshot of the emoji keyboard in Bing: