Supposedly, about 90% of women who can orgasm pre-op can do so afterward too. In any event, it took me a few months to figure out how, but I can orgasm from clitoral stimulation, primarily. (My first post-op orgasm was in my sleep 3 weeks after GRS, so I knew it was possible, at least.)
I do get a little wet (and squirt a bit at orgasm), and I've recently noticed that I get wetter from penetration - the longer it goes on, the more my body seems to respond, versus a little bit from clitoral stimulation alone.