Supermarket tomatoes are usually grown in greenhouses, so the fruit tends to be thin-skinned, but tomatoes grown outdoors and ripened under the sun tend to have thicker waxy skins that can be unpleasant to eat and can ruin the texture of pasta sauces.
By peeling the tomatoes before using them, you can not only make them easier to eat; it also exposes the vibrant colored flesh under the dull skins which can make salads more colorful.
As a tomato cooks the cell walls in the flesh break down, causing the tomato to dissolve. By quickly boiling and chilling the tomato it allows you to dissolve a layer of tomato just under the skin without cooking the tomato through. This releases the skin making it slide off very easily.
This depends on the size of the tomato and how ripe it is. The larger the tomato, the longer it can take, and the less ripe the tomato, the longer it will take. I usually let cherry tomatoes go for 2-3 seconds while I start out with 5 seconds for bigger tomatoes. 
I usually score them as it makes it much easier to tell when they’ve blanched for long enough (the skin will start to pull away from the are the tomato was scored). Scoring them also makes tomatoes easier to peel once they’ve been blanched. That being said, it does leave little marks on the bottoms, so if you want the tomatoes to maintain a perfect shape, you can skip this step.
You can steam them or microwave them, but both of these methods have their drawbacks. When you add things to a steamer, you have to open the lid, releasing the steam. It takes a while to get the temperature back up after you’ve added the tomatoes and closed the lid. This can result in more of the tomato being cooked than if you were to blanch them in boiling water.
Similarly, microwave ovens heat unevenly, so some parts of the tomato may get overcooked while other parts won’t get hot enough to make them easy to peel. You’ll also need to do them a few at a time to make them cook as evenly as possible so starting and stopping the microwave a bunch of times is a bigger hassle than just dunking them in boiling water. 
So many possibilities here. I love peeling tomatoes when I use them in salads as it makes them juicier and exposes the vibrant colored flesh making the salad more colorful. Here’s a recipe for my Tomato Purslane Salad as well as my Watermelon Tomato Salad.
For sauces like my Basic Tomato Sauce, I like to peel the tomatoes because it avoids those waxy curls of skin that tend to get stuck between your teeth.
Ingredients
- 5 tomatoes
Steps
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Using a sharp knife score and "x" into the bottom of each tomato. Be careful not to score them too deeply or they will fall apart when you blanch them.
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Prepare a large bowl of ice water.
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Bring a large pot of water to a boil and lower the tomatoes into the water a few at a time.
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Blanch the tomatoes for 5 seconds and transfer them to the bowl of ice water using a slotted spoon.
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For cherry tomatoes you should be able to pop them out of their skins by giving them a twist and squeeze.
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For bigger tomatoes you can use a paring knife to get you started and then you should be able to peel the tomato using your fingers.
