I am not much of an electrician.
Don't worry. I'm not much of a cook

. I'll try to make this as simple as simple can be.
If I leave them and install a fan in that general area, can I somehow tie into the light wiring to power the fan?
Thanks!
Great that you're asking all the right questions here. Not an electrician but plenty of common sense, something that's in short supply around here recently.
It all depends how much current (amps) the lights are now pulling. If they are all LED's no problem. If they aren't, it may be worth the effort and small cost of installing them. Easy if you look in the chandelry on this site. Advantages are huge. All the lights on, all the time and they don't pull your batteries down. The other consideration is, "how many amps do the fan(s) pull?"
Add up the amps of all all your cabin lights (minus the two you are removing) and add in the amperage of the two fans and compare this to the amperage rating of the "CABIN LIGHTS" breaker to see if the circuit can handle it. (AMPS = WATTS / VOLTAGE) Always count on everything being on at once. Report your findings in this post and we'll help you along. It's not like we've all got a heavy schedules here.
Do you think I just turn one of those existing lights counter clockwise to remove it?
They look similar to my lights in the aft berth. Can't say I've ever had cause to remove them. Try carefully inserting an Exacto knife blade under the casing and gently prying out on the casing. No luck, go back to CCW unscrewing them. No luck, I'll check my boat and see what they're like.
Keep us informed. I like these virtual jobs. No fuss, no mess.