Heat the oil in a deep pan and saute the garlic and red pepper flakes just until you can begin to smell it and add the anchovies and parsley and saute for a moment more. Add the crushed up canned tuna and mix it in well.
Add the can of tomatoes and 1/3 can of water. Crush the tomatoes with a potato masher and add the salt, sugar and black pepper.
Cover and cook on a low simmer for 15 minutes add the olives and it's done.
Put on a pot of water for the pasta and when it comes to a boil add the pasta and cook according to package instructions.
Notes
I don't really have any extra tips or tricks for the recipe except to say that it really only simmers for 15 or 20 minutes. Cooking longer will just kill it's flavor.