Bring a large pot of heavily salted water to a boil. Meanwhile, thinly slice 3 garlic cloves. Coarsely chop ½ cup pitted black olives. Drain and coarsely chop 2 tablespoons nonpareil capers. Pick the leaves from 8 fresh parsley sprigs and finely chop until you have about 2 tablespoons.

Heat 2 tablespoons olive oil in a large high-sided skillet over medium heat until shimmering. Add the garlic, 4 anchovy fillets, and ¼ teaspoon red pepper flakes. Cook, stirring occasionally and breaking up the anchovies with the back of a wooden spoon, until fragrant, about 2 minutes. Add the olives and capers and cook for 1 minute.

Add the remaining ¼ teaspoon kosher salt and 1 (28-ounce) can whole peeled tomatoes and their juices, breaking up the tomatoes with your hands into bite-sized pieces as you add them to the skillet. Stir to combine and bring to a simmer. Reduce the heat to maintain a gentle simmer and cook, stirring occasionally, until the flavors meld, about 10 minutes. Meanwhile, add 12 ounces dried spaghetti or linguine to the boiling water and cook 1 minute less than the package instructions for al dente.

Reserve ¼ cup of the pasta water. Drain the pasta. Add 2 tablespoons of the reserved pasta water to the sauce and simmer, stirring occasionally, until the sauce thickens slightly, about 1 minute. Add the pasta and toss continuously until the sauce thickens a bit more and coats the pasta, about 1 minute more. If the sauce is too thick, add the remaining pasta water. Garnish with the parsley.