Cut the tomato into bite-sized pieces. Halve the avocado, remove the seed and peel. Mash 3/4 of the avocado and mix with the sauce ingredients. Chill the tomato, mashed avocado sauce, and remaining avocado in the fridge for 15 minutes.

Clean the shrimp by removing the vein, rinse with water, and pat dry with a paper towel.

Boil water in a pot, add salt and spaghetti, and cook for 1 minute longer than the package instructions. Add shrimp in the last minute and cook until they change color. Cool the pasta and shrimp in cold water and drain.