Add half of the can of chipotle pepper (about 3 whole chipotles, the can of tomatoes, and the salt to a food processor or blender.
Blend on high for 2-3 minutes, or until all of the ingredients are broken down and become smooth. Salsa will not be completely smooth, and will still have some texture.
If a smoother or thinner salsa is desired, add water to the blender one teaspoon at a time.