Heat oil in a large stock pot on medium high heat. Add in onions and garlic. Saute stirring occasionaly for 3 minutes. Add in jalapenos and saute for 5 minutes. Add in tomatoes. Cook stirring occasionally for 5 minutes or until the tomatoes start to get mushy.
Next, add in the tomato puree. Cook slightly covered for 10 minutes.
Pour in the water, chayote and corn. Stir the soup and cover slightly. Continue cooking for an additional 10 minutes.
Lastly, add in shrimp and cilantro. Cook completely covered for 10 minutes on medium low.
Serve the soup with some nice crusty french bread, fresh tortillas or saltine crackers.