to hit the long head MORE than the other heads, any type of overhead or tricep extension where the triceps are in a stretched position.
outer bi? welcome to wonderland. your probably thinking brachialis, which can be hit by hammer curls.
there are no specific exercises that will limit the stimulation to such a particular region in a muscle designed to work synergistically. the triceps complex being made up of 3 muscles work synergistically, but the amount of prestretch and the different origins can make it more "customizeable" for exercises. the differences in the inner and outer head of the biceps is negligible and should be worked as a whole. most people think that the brachialis burning sensation is the "outer" bi. myth, just like the iliopsoas and rectus femoris burning during hanging leg raises is the "lower abs".