Wash the agretti well and remove any woody stems if necessary. Bring 5 quarts of water to the boil in a large saucepan and add 1 tablespoon of salt and the agretti. Blanch for a couple of minutes, then remove the agretti with a slotted spoon and refresh in cold water.
Bring the water back to a boil, add the pasta, and stir. Bring back to a boil, cover, and cook for 4 minutes. Remove from the heat and let sit in the water in the tightly covered pot for 8 to 10 minutes or until just al dente.
Meanwhile, heat the extra virgin olive oil in a skillet, add the garlic, and cook for a minute or two, then add the anchovies, mash slightly, and add the chile flakes and scallions. Cook for a couple of minutes, add the well-drained agretti, and continue to cook until tender but still with a bite—a minute or two.
Drain the pasta, add to the pan, and toss well. Drizzle with more olive oil. Season to taste, grate over some fresh lemon zest, and turn into a hot serving bowl. Grate over some more lemon zest and serve as soon as possible.