Just cut it or peel it off the rock, it's not too small. I prefer cutting, as peeling them seems to do more damage. The issue is going to be what you leave behind. Even a tiny scrap of xenia will certainly grow back. What I've done with success is to wait until the "stump" sprouts some tiny polyps, then inject each one with kalk paste. So long xenia.
Xenia spreads like mad and can be a pain in the butt. I even had a stalk grab onto a nerite snail when it lingered a little to long at its base. A good thing to do, if your aquascaping allows it, is to give the xenia their own little rock island off to the side. That will prevent them from growing where you don't want them. If you place the island against the glass, the stalks will grow right up it. Then they can be very easily razor bladed off for trade.
