Hot then cold or the other way?
Best way is to score an "X" in the bottom - just enough so it's through the skin - and drop it in simmering water for about 10 seconds. Plunge quickly in cold water to stop any carryover cooking and then peel with a paring knife.
Here's a food52 video: http://food52.com/blog...
I love Amanda's tomato in the freezer method it works so well.