Hello Sam,
Thank you for posting your question on Microsoft community.
I appreciate you for providing details about your query.
Unfortunately, close or minimize button can only appear when using mouse or touchpad.
However, you may refer this article for more information.
Refer:
Start, find, and close apps on Surface
http://www.microsoft.com/surface/en-us/support/apps-and-windows-store/start-and-close-apps#close
Note: Please refer "How do I close an app?" section in the above article.
I hope this information helps.
Please do let us know if you need any further assistance.
Thank you