Fregola, sometimes referred to as fregula, is a lumpy, pebble-shaped pasta from Sardinia that is formed by hand and then lightly toasted until golden. Fregola comes in small, medium and large grains and is available at specialty markets or by mail order from Formaggio Kitchen (888-212-3224 or formaggiokitchen.com) or from chefshop.com.
Heat the olive oil in a large skillet. Add the garlic and cook over moderately high heat until fragrant, about 30 seconds. Add the chopped tomatoes and cook until softened, about 3 minutes. Add the water and bring to a boil. Stir in the fregola, cover and cook over moderately low heat, stirring occasionally, until tender, about 17 minutes.
Add the clams to the skillet in a single layer. Cover and cook over moderately high heat until the clams open, about 4 minutes. Discard any clams that do not open. Season the fregola with salt and pepper. Spoon the fregola, clams and broth into shallow bowls. Sprinkle with the coarsely chopped parsley and serve at once.