Heat a large cast-iron skillet over medium-high heat. Add tomatoes, and cook, turning occasionally, for 20 minutes. Add chiles, and cook, 2 minutes. Add garlic, and cook, until all vegetables are blackened and tender, 4 to 5 minutes more.
Transfer 1 tomato, chiles, and garlic, to a food processor, and process until smooth. Add remaining tomato and salt. Pulse until a chunky salsa consistency is achieved.