Place 6 quarts water to boil and add 2 tablespoons salt. In a 12 to 14-inch saucepan, heat olive oil over medium heat until smoking. Add the onion, season with salt and pepper and cook for 3 to 4 minutes. Add the parsley, 1/2 cup wine, tomatoes and cook for another 3 to 4 minutes. Add the calamari and the pepper flakes and season, to taste. Stir through to mix the ingredients and remove from heat and let cool.
When the pot of water reaches a rolling bowl, add the pasta and cook according to the package directions until just al dente. Drain well and pour the hot, cooked pasta into the saucepan with the calamari. Return the pan to the heat and toss until well coated and the calamari is completely opaque. Pour into a heated serving dish and sprinkle with toasted breadcrumbs, drizzle with extra-virgin olive oil and garnish with parsley and grated pecorino cheese. Serve immediately.