If you have fresh tomatoes, cover them with water and bring to a boil. This will only take a few minutes.
Discard the water used when boiling. Place the boiled tomatoes in the blender along with the chipotle, onion, garlic, water, and salt. Blend until smooth.
Saute the onion in oil, then add the chipotle tomato sauce. Bring to a simmer. Add the shrimp and cook until it is no longer pink.
You can serve it with Arroz blanco and ensalada de nopales (cactus salad).