In a 6-quart Dutch oven, bring 4 quarts of salted water to a boil over medium-high heat.
Add spaghetti, cooking about 6-7 minutes until al dente. Drain and set aside.
Return the Dutch oven to the stovetop and heat 2 tablespoons of olive oil over medium heat.
Add the shrimp, salt, and ½ teaspoon of the red pepper flakes. Spread evenly across the bottom of the pot and cook until the bottoms pink and slightly brown, about 45-60 seconds. Flip and repeat until shrimp are just cooked through.
Remove the shrimp and place in a small bowl to the side.
Reduce heat to medium-low, and add additional 1 tablespoon of oil to the pot, as needed.
Add onion and garlic to the oil and cook until onions have softened, about 3-5 minutes. Stir frequently to ensure the garlic does not burn.
Add the diced tomatoes, remaining 1 teaspoon of salt, sugar, remaining 1 teaspoon red pepper flakes, oregano, and white wine.
Stir and bring the sauce up to a simmer. Simmer for 5-10 minutes until the sauce has thickened.
Return the shrimp (and any accumulated juices) to the sauce. Add the parsley, stirring to incorporate.
Add the cooked spaghetti back into the pot, toss until evenly coated and heated, then remove from heat. Serve immediately.