Sounds like there is not a lot wrong and the clutch is just suffering from standing. I suspect the clutch may free up with a bit of running so you could
temporarily take up the 1/8 slack at the leaver which will lift the plates slightly more
kick it over a good few times with the clutch pulled in
put the bike on its centre stand and make sure the back wheel is off the ground. Then start it up run it a few minutes with the clutch in to spread the oil and then slip it in gear but keep the clutch in too. The back wheel will probably spin but a few dabs on the back brake may let you run the bike clutch in, in gear and rear wheel stationary. This will warm the clutch and may free it up without stripping and cleaning.
Let us know how you get on
Hope this helps, Andy