Grilling tomatoes for salsa brings a whole other flavor layer to the mix, a deeper, richer flavor. Unless you grill the tomatoes over a wood grill, you won’t get a big smoky flavor, but the charred skins will add depth.
Grill the chiles, too (jalapeno, serrano or other green chiles, like New Mexican green or poblano) and you’ll notice you get a bit more heat out of them than fresh chiles.
You can use fire roasted tomatoes for other things besides salsa. You can make a fire roasted pasta sauce, for example, replacing canned or fresh tomatoes in your favorite recipe with grilled tomatoes. Or you can grill some red onion while your at it, and then chop up the charred onion and tomatoes for a garnish for grilled chicken or fish.
Use either the round variety or the plum tomatoes (Roma). It doesn’t really matter. Even though it’s not tomato season, they’re available year round, and grilling them is a good way to boost their flavor punch when they’re not in season.
It’s really simple to grill tomatoes. Just put them on a fairly hot grill and let them grill until they’re charred to your personal preference. (I do core them before grilling, but you don’t have to.) I like to grill them until they’re black on one side (could take 5 to 8 minutes on the first side) and then flip them and grill on the opposite side. I don’t let the entire surface skin get black like I do with my chiles, but then again, I’m usually grilling chiles to get rid of the skin, and for the tomatoes, I keep the blackened skin for it’s flavor.