New to Mikrotik:

I see a Radius section, can I set this up as an actual Radius server? I would be authenticating wireless users via Mac addresses.

No, that is for setting up the router as a RADIUS client.

There is an optional User Manager package (this forum has a section for it, the manual is on the wiki) that acts as a RADIUS server.
In my opinion an external dedicated RADIUS server is better and far more capable, but User Manager may do what you need it to do.

You would still configure the router via the section you found when you have finished setting up the RADIUS server and configure the router as a client with the parameters to reach the RADIUS server (can reside on the same router, but it is still a client/server relationship via the loopback interface).

New to Mikrotik:

I see a Radius section, can I set this up as an actual Radius server? I would be authenticating wireless users via Mac addresses.

Have you picked out a radius server yet? I have tried many in the past years, and even developed my own the past couple of years. I would be willing to give you some advice if I knew what your looking for in terms of specifics you desire.

New to Mikrotik:

I see a Radius section, can I set this up as an actual Radius server? I would be authenticating wireless users via Mac addresses.

Have you picked out a radius server yet? I have tried many in the past years, and even developed my own the past couple of years. I would be willing to give you some advice if I knew what your looking for in terms of specifics you desire.

I already have 2 Radius servers in place (Dialup Admin), I just thought it would be cool if I could use our new router for this purpose. I could get rid of 2 pc's in our server room.

Thanks for the offer tho, I really appreciate it.