Heat the olive oil in a pan. Add the garlic, onion, chili flakes and oregano. Saute until fragrant.
Add the olives and capers. Continue sauteeing for another minute.
Pour in the chopped tomatoes. Season with salt, pepper and a little sugar. Simmer, covered, until reduced by a quarter. It takes about 10 minutes.
Turn up the heat. Add the clams to the sauce. Stir. Cover the pan and cook just until the shells open.
Turn off the heat. Taste the sauce and adjust the seasonings, if needed.
Add the pasta to the clams and sauce. Toss well.
Divide the clams pasta arrabbiata among three bowls. Garnish with chiffonaded basil and and serve.