Well, there is already a Galician form of
Juana which is
Xoana. I looked through the Galician Wikipedia on Xián and all the links to other language versions of Wikipedia point out to
Julian. Also, the page points out that Xulián(a) can also be used as a "variant" of Xián/Xiana (don't know why they call Xulián a variant but I presume Xián is more often used in Galicia than Xulián).
My PNL:
http://www.behindthename.com/pnl/149249