my arms are huge and i need to cut but have no idea what muscle it is or how to work it out..this muscle..
Any kind of pressing movement shoulder helps with that, i.e. benching and overhead pressing. You can also check out the mountain dog shoulder workout on T-nation, which is a pretty high volume program.
The muscle on the right in that picture is the front deltoid. Russia basically summed up what movements work that muscle. You can also do shoulder raises to work your delts.