Heat a large skillet or comal over medium heat. Add tomatoes, onion halves, garlic cloves and jalapeño.  Cook until charred patches appear on vegetables and tomato skins begin to peel.  Remove husks from garlic cloves.

Transfer vegetables to a blender container.  Add salt, and water.  Pulse on low setting keeping the salsa texture chunky. Taste and adjust salt if needed.

Transfer to a salsa bowl and serve.