I am a PhD student in computer science, and chose to specialize in a research area that was interesting to me personally, but not interesting to most tech companies. I am approaching graduation and I am not sure where to find a job. What do I do now?
The specialised research area of your PhD topic probably has a wider range of related fields which are relevant to prospective employers. I suggest identify those fields and use them to build your own resume, and also to identify prospective employers. Search those terms in job sites and identify employers that way.
Unless committed to specifically continue research in a focused line of investigation, then in most cases, I believe that job seekers in your position are really looking for work which utilises the broader skills that they have generated through their post-graduate degree. Try to take a step back to think of the skills you have gained.
The more generalised skills such as general subject knowledge, investigation, research community networking and research are more likely to be of value to your prospective employer than your expertise in your own specific topic.
In most cases, people don't specifically use their PhD after graduation (unless they go on to work for a university or government research department). Most people don't even directly use their Bachelor degree. So your problem isn't the end of the world.
The first year of work usually consists of your workplace showing you how they do things, and you learning their methods and procedures, their ways of dealing with clients, and solving problems that university didn't prepare you for.
So sell yourself as someone who works well with people, is willing to continue learning, and is humble enough to work under others without assuming you know everything just because you have a PhD.
Also, don't expect to skip the lower paid positions straight to the top due to your education; the Bachelor degree graduate who has been at the company for 4 years while you studied your PhD has probably picked up a lot of company knowledge and is more useful than you will be in your first month. You'll likely get a bit of a wage boost over a bachelor graduate, but not straight to the top. Set your expectations appropriately and workplaces will be more willing to give you a shot.