Bring a large pot of water to a rolling boil. Add dried pasta to the boiling water and stir. Cook pasta for approximately 7 minutes, or until done, but allow pasta to be firm.
Drain pasta into a large colander and run cold water over the pasta to stop it from cooking. Set pasta aside in the refrigerator to keep it cold.
Rinse cooked shrimp. Be sure to devein and remove shell and tails. Pat dry.
Remove pasta from the refrigerator and add diced veggies (bell pepper, celery, tomatoes, and shallots).
Add shrimp, imitation crab, seasoning salt and black pepper to the pasta mixture.
Add mayo to the pasta mixture and mix all ingredients until creamy.