Okay, so you are trying to make your own salsa, or your own spaghetti sauce, or you just come across a recipe that asks you to skin tomatoes. Skin tomatoes?!? Those were my thoughts before I learned how to blanch them. You skin tomatoes by blanching them. Please don't attempt to take a peeler to them, this thought crossed my mind as well because it seems legit, but that's not the way people. Blanch, then peel, that is how its done.
How to blanch tomatoes
Rinse tomatoes then cut the core out of the top with a sharp knife (do this in a circular motion at the top, removing the core and stem).
Cut two slits forming an x in the bottom of the tomato at the base
Fill a large pot with water and 1 Tbsp. salt
Bring to a boil
Add tomatoes and blanch for 3-5 minutes or until skin starts to peel
Remove tomatoes from the boiling water and add tomatoes to a large bowl filled with ice filled cold water (this stops the cooking process)
Let sit in the chilled water for 10-15 minutes
Remove from water and peel (the skin will come right off as you peel it away)