The company I worked for hired a CEO. A large, boisterous man who at first take looked like a great leader. He turned out to be an ahole and engineered all sorts of bad things for our company, including screwing up our agent pay plan which over time harmed the company in all sorts of ways. I came to dislike the man intensely to the point that I wished ill upon him. After a bit, I came to recognize that my feelings were wrong, so I actually began to pray for him. The gist of my prayer was that he'd come to recognize what an ahole and destructive force he was, repent, find the Lord and as a result repair the damage he'd done and help make our company what a good thing it was before he came along.
About a year later he was arrested and sent to prison when it was discovered that in addition to being an ahole and destructive force, he conspired with a couple other senior executives and were stealing and diverting company funds to themselves. One of his co-conspirators, when being led out of the building by security, remarked "Will this affect my pension?"
The moral of the story is that when you pray for aholes to repent, they do generally get their just deserts.
Personally I always like Proverbs 25:21-22, repeated in Romans 12:20. In addition there are many verses in the OT and NT that speak of how you are to react to those who do ill to you. You will be surprised how better you feel when you find yourself praying for those who are less than nice to you. It makes you a much better person for it, and it might just make the ahole a better person too.