Bring a large pot of lightly salted water to a boil. Cook spaghetti in boiling water for 8 to 10 minutes or until al dente; drain.
Heat oil in a skillet over low heat; cook garlic in oil until golden. Add sieved tomatoes, and cook 5 minutes. Stir in anchovies, tomato paste, capers, olives, and red pepper flakes. Cook 10 minutes, stirring occasionally.
Toss pasta with sauce, and serve.
