DaVita offers a program called SIP (student internship program). They work with the student currently in an educational program, such as Prairie State's dialysis tech program, and offer clinical education and time in training from the clinical perspective. You can inquire about this through the instructor or at a DaVita clinic.
Keep in mind, SOME clinics will hire and fully train new, completely unexperienced people to be dialysis technicians. It is rare, but the opportunities are out there.
I'm not against taking a college course for dialysis technicians, but most of these programs do not offer certification at the end of the program because they simply cannot. Whether you sit for the NANT exam, or the BONENT, you will need at least 6 months experience working as a dialysis technician, which you won't have after successful completion of the college program. You will still need to gain some type of employment or clinical internship to get that experience before becoming a state certified dialysis tech.
It's not a bad career move though. I've been at it going on 9 years now. I love it, but I was lucky back in my day. I faxed my resume to a clinic that was hiring, and was fully trained in a 8-10 week program they put together. At that time, I wasn't even experienced in healthcare, let alone nursing or patient care. That was then, this is now. You just need to keep your eyes open for the opportunity.