first off, editing tags are a standard element of most forum software, it might not even be possible to do so.
secondly, they are important for thread consistency, e.g., it is important to show that a post was edited after it was quoted for example to explain where the difference originates.
So, I don't think removing them would be a good idea, even if possible.
edit: Simon was faster. ;)
possible might be a visual shift to right-aligned to put it to the side where "report" etc resides.