I've never made salsa, but I have two suggestions as far as tomatoes go. One, there's a trick to peeling a tomato. Two, you might be better off with canned tomatoes, if you don't want them raw. Canned tomatoes are actually riper than any fresh ones you'll get at the supermarket, but they are cooked as part of the packaging process. I like San Marzano tomatoes. (The ones in the almost-generic looking cans are good.) Might not be the right flavor for salsa, though.