Warm olive oil in a large skillet over medium heat. Add the garlic, anchovy paste and red chile flakes, cooking just until the garlic turns fragrant (1 - 2 minutes). Stir frequently to break up the anchovy paste and keep the garlic from burning. Add spaghetti to the pot of boiling water, and cook until al dente (a little chew left to the texture) or according to the instructions on the package. Add tomatoes (with juices), olives and capers to the large skillet, stirring to combine. Cook for 10 minutes (about the same amount of time needed to cook the spaghetti), stirring occasionally. Season sauce to taste with kosher salt.