My dog exhibits obsessive behavior around digging in the corners of the windowsills. We put contact paper down because he was eating the paint chips but now is pulling up the paper in the corners. What do you recommend?

Is this behavior new? When and how did it start? Are there any triggers (noise, smell or visual) that he reacts to?
 
How often does he display the behavior – can he be interrupted – does he do it when you are  home or when you are absent? You might have to place a camera towards that spot to answer that question.
 
You can use a “remote” aversive such as Scat Mat or motion active canned air to deter him from that area – or place an x-pen to deny access.  But, I am curious as to the motivation of the behavior and it being particular to  that one spot. If deterrence works then there is most likely a trigger there and you can do more investigation as to what triggers the behavior. However, if your dog picks a new spot then we need to “dig” further into reasons for the behavior which can have several reason such as medical, seizure disorders, eye or metabolic problems in addition to anxiety or compulsive disorders  or escape drive behaviors.
 
Good luck and keep us posted!