Introduction: How to Skin Tomatoes. It's summer!  Time to grow or buy huge quantities of delicious tomatoes for your favorite summer tomato dishes.  Peeling or skinning tomatoes turns out to be the easy part - in fact, it's so easy a 3-year-old can do it.  Just follow these easy instructions, and you'll be making great tomato soup, salsa, or pasta sauce in no time flat.
i just processed about 22 pounds of tomatoes in about half an hour, including extra time to accommodate my assistant's* help. :)
*Corvidae just turned 3 yesterday!  She loves helping out with fiddly food-prep processes, especially if they involve the stove and/or ice.  If you let your toddler (or older kid) help in the kitchen, make sure they've got a nice stable platform (we use a folding utility stool for Corvidae) and that they're smart around hot and/or sharp objects.  We're trying to scald tomatoes, and hopefully NOT innocent bystanders.  Step 1: Tools and Ingredients. You'll need:
- a pot full of boiling water
- a bowl full of ice water, and more ice to add as needed
- a slotted spoon
- a sharp knife
- lots of beautiful fresh tomatoes!  
I got these Early Girls from my favorite tomato growers, Wild Boar Farms.  Soon they'll have tons of gorgeous and amazingly delicious heirloom tomatoes at the market, but I prefer to roast and freeze those, and their skins are so thin they don't require peeling. If you don't live in the SF bay area, I highly recommend buying some of their seeds so you can grow your own. Step 2: Staging (set Up Your System). - Fill a medium to large-sized pot with water, cover, and crank the heat so it comes to a boil quickly and efficiently.
While you're waiting for the water to boil:
- Fill a medium to large-sized bowl half-full with ice, then cover with water.  Place it near the stove, but not so close it heats up from the boiling water.
- Wash your tomatoes, and remove stems.
- Make a small X in the skin at the flower end (opposite the stem) and place near the stove. (see photo for detail)
Check out my staging choices in the picture below, then modify as needed to suit your situation. Step 3: Boil Tomatoes. Dump tomatoes into boiling water, and cook for roughly 30-45 seconds.  (Start counting time immediately - no need to wait for the water to reboil.)
This time will vary according to the size of your tomatoes (smaller tomatoes will cook faster!), the size of your pot (larger quantities of water have greater thermal mass!), and the number of tomatoes you drop in each time (more thermal mass of tomatoes drops the water temperature!).
The goal is to boil the tomatoes just long enough to cook the outer millimeter or so of tomato skin and connective tissue so the skin will detach easily, while leaving most of the tomato in a nearly-raw state. Do some test runs, and adjust your timing as needed.  If you see the tomato skins starting to split down from your original cut, they're definitely done - yank them out immediately, and consider dropping the time for your next batch. Step 4: Cold Shock Tomatoes. Scoop your tomatoes out of the hot water with your slotted spoon, making sure to drain any excess, and drop them into the ice bath.  Leave them until cool, then set out on the counter stem-end down while you process the rest of your tomatoes.
Remember to add more ice (and remove an equivalent volume of water to avoid spills) on a regular basis to keep the water bath nice and cold. Step 5: Peel!. Now the peels should practically slide off of your tomatoes!  Sometimes a paring knife comes in handy for damaged areas, or tightly adherent skin around the stem, but it's still ridiculously easy.
I prefer to peel over one bowl, then store the peeled tomatoes in a second bowl to avoid mess.  This way, you can squeeze out the accumulated tomato skins when you're done to make a nice glass of tomato water!  Just add a pinch of salt, and it's your treat for virtuously processing all those tomatoes.
Now get started on your favorite tomato recipes!