I'm a practitioner who is struggling with techniques from some difficult academic papers (computer science & mathematics). How can I find "tutors" (graduate students perhaps?) who are willing to work on an occasional basis to help me understand specific papers?
I would contact the math department at your local university.
I would be prepared to pay them well, they have lots of responsibilities and demands on their time as it is and it can be quite a lot of work to work through an academic paper, not to mention the effort involved in compiling background material to essentially teach this material to someone else.
If I were a graduate student still, I wouldn't do it for less than around $75 an hour, because the time I would have to put in to give essentially 2 hours a week of this kind of tutoring would be closer to about 6 hours, so even then it starts to sound barely worth it.