In a Dutch oven or large, heavy skillet, heat the olive oil over medium heat. Add the onion and sauté for about 3 minutes, or until translucent. Add the garlic, chili flakes, cayenne pepper, oregano, and thyme and stir for 1 minute, or until fragrant.

Add the wine and stir to mix well. Add the tomatoes and their juice and mash gently, using a potato masher or a large serving fork. Stir in the tomato purée and salt. Let the sauce simmer over medium heat for 15 minutes. Add the sausage and simmer for another 10 minutes to blend the flavors. Cover and remove from the heat.

While the sausage is simmering in the sauce, bring a 6-quart pot two-thirds full of lightly salted water to a boil over high heat. Add the pasta, decrease the heat to medium-high, and cook, stirring occasionally, for about 10 minutes, or until al dente.

About 5 minutes before the pasta is ready, return the sauce to the stovetop and reheat over medium heat. Gently stir in the shrimp, scallops, and fish to mix well. Cook uncovered, stirring occasionally, for about 5 minutes, or until the shrimp turn pink and the fish and scallops are barely opaque at the center.

Drain the pasta in a colander and shake it dry. Add it to the sauce and toss gently to coat evenly. Divide among 4 large plates or shallow bowls.

Serve at once.