In a food processor add avocados, cashews, basil leaves, lemon juice, garlic cloves and sea salt. Process until chopped and mixed, about 45 seconds. Stream in olive oil and continue processing until a thick paste is formed. Refrigerate until needed.
Bring a large pot of water to a boil. Add a bout 1/4- 1/2 cup sea salt and cook pasta to al dente, following directions on package.
Wash and cut tomatoes. Set aside.
Add olive oil, garlic and chili pepper flakes to a medium sized frying pan and heat over low heat until garlic slices begin to bubble and just slightly brown, about 10-12 mins. Add shrimp keeping heat still on low and cook for 2 1/2 mins per side. Remove shrimp from oil and set aside.
Once pasta is al dente strain and add to a large bowl. Stir in avocado pesto, add tomatoes and shrimp.