Hi Njoy,
Well I guess I steered you wrong there--I (for some reason) assumed the typical metal brackets.
If they look like solid ceramic and they're embedded in a tile wall, these could well have been put down with mastic at the same time as the tile. So if you get them out of there, you could have a bit of a chore on your hands regarding the gaping holes. I would probably think twice before doing that.
Now some ceramic brackets are more decorative--and as such ARE connected to metal brackets. I'm beginning to think you don't have these--but you can tell by looking underneath the brackets and seeing if there are formed metal pieces beneath. If it's these, it's easy--as you probably only have to lift them upwards to free them from the brackets.
So, at this point can you tell which it is and get back to us?
Thanks njoy,
-k2 in Colorado