Preheat broiler. Spread a sheet of aluminum foil over broiler pan, place the tomatoes and jalapenos on it and broil. Turn occasionally. Remove the jalapenos after about 10 minutes, when the skins are browned and blistered, and place in a plastic bag. The tomatoes will take an additional 10 to 15 minutes until the skins are blackened and the tomatoes are softened. Remove to a plate to cool.
When tomatoes and jalapenos are cool enough to handle, rub off the skins, remove the stems, and put the flesh and juices in a food processor or blender. Be careful peeling the jalapenos and wash hands thoroughly after handling. Blend or pulse jalapenos and tomatoes until coarsely chopped. Set aside.
Pour olive oil into a large heated skillet or saucepan over low heat. Add the onion and garlic and cook, stirring occasionally, until softened but not browned, about 10 minutes. Pour in tomatoes and jalapeno mixture and salt, stir and cook for 10 minutes, stirring occasionally.
Stir in cheese and cook 5 minutes, stirring frequently to incorporate the cheese as it melts. Pour into a bowl and serve immediately with tortilla chips or scoop up with heated fresh corn tortillas.
Recipe courtesy of David Bowers, author, "Bake it Like a Man"