Fill a large saucepan two-thirds full of cold water. Bring to a boil. Pour in a small handful of salt. Add spaghetti, pressing with a wooden spoon to submerge it. Stir several times as the water returns to a boil. Cook until al dente, about 10 minutes.
Meanwhile, cut garlic cloves in thin slivers. Reserving 2 anchovy fillets, cut the remaining 4 in three pieces.
Pour olive oil in a small skillet. Over low heat, gently cook garlic until it begins to color but does not brown.
Drain pasta, reserving 1 cup of cooking water. Return pasta to saucepan. Over low heat, stir in anchovies and garlic with oil. Season to taste with sea salt (you may not need any) and hot red pepper. Stir in arugula and heat just until slightly wilted, adding pasta water if needed for a saucy consistency.
Garnish each serving with breadcrumbs, a whole anchovy and, if using, grape tomatoes.
Spaghetti with Anchovies and Toasted Breadcrumbs https://tavolatalk.com/spaghetti-with-anchovies-and-toasted-breadcrumbs/