Prune... no. Never in flower.
Defoliate... perhaps. I like to remove some of the larger interior leaves, but only if I feel they're blocking light to bud sites.
I agree with Tead. You can defol fan leaves if they are blocking light to lower bud sites. I thinks it's mostly recommended to do a few per day so as to not stress the plant too much, but I have heard of people doing it all at once so they don't continually stress the plant. Soo... yeah, two schools of thought there.
I'm in the slow and steady school of thought. Less plant material removed = less stress induced in plant = happier plant. Seems logical, but then again, logic often fails me in the grow room.
I was just reading a tutorial post today, and the author mentioned that he removed any under-sized shoots during the first 2 weeks of flowering. This is a different scenario than yours, as it was an indoor SCROG setup, but his logic was that he wanted the plant to focus all the energy on the main colas. And as mentioned, every time you hurt the plant, it may need some recovery time.
I'm guessing that by "prune some of the leaves" you meant defoliate. That should be fine, as the guys said before mine. Though you are in direct sunlight, as you mention, so you probably have pretty good light penetration to all your bud sites. If not, remove or trim leaves to expose the hidden bud sites, as you see fit. Whatever way you go, you have some nice looking plants!