From a theory POV what is it mean when composers like Scriabin and Chopin are remarked as having daring harmomies? I am guessing this is outside the scope of the traditional music vocabulary? Any examples and can they be incorporates into guitar music?
Listen them and find out. How's the rest of your harmony? If I asked you to harmonise in 3rds in the key of C major could you do it?
I can harmonize in C in thirds on staff paper. Regarding Scriabin, I have played through the op22&74 and a couple etudes. Op. 74 is nothing like I have heard before. I can't really understand how to extract the underlying harmonies in them formally though. I suppose that will require some advanced understanding. Is it just best to listen and incorporate?
^^^ Pretty much. It's not like you can say "well if you harmonise with the b3 to to #6 over the cadence leading to a key change you will achieve daring level harmonies". Better to just listen and imitate.