if you are talking about ceramic tiles like these you are going to have a hell of a bad time working it out
first off cause they dont come separate. they come in a 30x30cm net that is then cememnted to the wall. you can pull one out, but im pretty sure you'll never get it back in as secure as it would be if you hadn't messed with it.
anoter thing is that those ceramic tiles are designed for use in bathrooms, so that they dont retain humidity or any form of liquid. they are really polished and you are going to have a huge hard time getting the paint to stick.
best choice would be to get some paints made to paint in glass and use that to paint watever you want, but only after the tiles are on the wall and the cement is dry and the filler is also dried.