You will have to undo the bolts at the top of the fender, and the headlight bracket too.
They are probably put on with sikaflex, which does take a fair bit to get off, so don't expect your paint to be in perfect condition afterwards. You might get the sideskirts off however you will be putting a fair bit of pressure on them so just be careful.
Normal masking tape if left on for a period of time and in the sun will dry and crack and comes almost impossible to get off by peeling it. Buy some quality 3M stuff from bunnings to be sure. Sure it might cost $15 but a respray is a hell of a lot more.