Well, okay, not necessarily red, especially if you, like me, didn't grow many red varieties this year. Of the 17 tomato plants I grew this year, I think only 4 of them are red. Most of them are orange/yellow. I'm not sure how that happened; I didn't plan it that way.
So, back to drying tomatoes. The past few years, I've dried them in the oven. It's really easy to do. Wash your tomatoes. Cut cherry & small tomatoes in half or quarters and larger tomatoes into 3/8" slices (or whatever). Put them on a baking sheet and bake them at 200 degrees or lower (my oven goes down to 170, which is what I used.) If you want, first brush them with olive oil and sprinkle them with herbs and/or minced garlic. (This makes it impossible--at least for me--not to eat every one of them right out of the oven, which is why I didn't do that last year.)
It's hard to say how long you should bake them--I seem to remember them taking a lot longer than I expected and leaving them in overnight--mostly 'cause I'm not good at keeping track. I'd say between 6-18 hours, depending on how small and how juicy your tomatoes are, how hot your oven is, how dry you like them... You get the idea. After about 6 hours, test them every hour or so by tasting one or two. If you're lucky, you'll have some left when you're done testing.
Also, and if you want to make clean up easier, line your baking sheet with parchment paper or silicone baking sheet. I put the tomatoes on baking racks to help with the air flow as well as cleanup, which worked fairly, with the exception of the smallest toms that fell between the wires.
When your tomatoes are dried to you liking, cool them, put them in containers (I like canning jars) or Ziploc baggies, and store them. (If you're a better person than I am and can resist eating them all out of hand.) You'll hear that you can store them at room temperature, but I'm paranoid, especially since I like mine with a bit of moisture left in them, so I store them in the freezer.
Use your dried tomatoes on pizza or bruschetta, in pasta sauce, in hummus or other dips, on sandwiches, or anything else you'd like.*
I had purchased a dehydrator last winter, so this year I dried my tomatoes using that. I've dried a few batches so far, at 140 degrees for about 12 hours. The photo above is of the tomatoes before drying. I'd have a photo or two of the finished product if I hadn't eaten most of them already. My goodness, those little things are yummy.
For better directions on drying tomatoes and for more ideas on how to use them just use the Google.
*Give this Sun-Dried Tomato Risotto recipe from Epicurious.com a try--with your own adjustments, of course. We love it!