I am going to use tile nippers to make a curve cut in ceramic tile. Will the edges still be uneven? Will I have to grind down the edges to make it smooth? If so, what tool would I use for this? Thanks.

This is just a rent house and we get ceramic for very cheap...placing tiles on the couter tops in the kitchen would improve the look drastically! Can I just put the tiles over the existing counter? The current counter is not tile...its just flat and plastic looking...and the ugliest red I have ever seen! Also I have heard that there is a chance that aspestice could be in it because it is an older home.