Combine water, tomatoes, half of the red onion, and minced garlic in a large pot.

Bring to a boil over high heat.

Reduce heat and simmer until tomatoes are soft.

Remove from heat and let cool for 2 minutes.

Transfer mixture to a blender.

Add chipotle peppers, tomato paste, and salt to the blender.

Blend until smooth.

Slice the remaining red onion.

Heat canola oil in a large saute pan over medium-high heat.

Saute sliced red onions until golden brown.

Add shrimp and garlic salt to the pan.

Cook for 2-3 minutes, or until shrimp turns pink.

Pour the blended sauce over the shrimp.

Simmer for 4-5 minutes.

Serve over rice, if desired.