Heat 1 tablespoon of oil in a large skillet. Add shrimp and season with salt and pepper. Cook 1 minute and transfer to a large plate. Set aside.
Heat remaining oil in skillet over medium heat. Cook diced onion until translucent and soft, about 5 minutes. Add garlic and red pepper flakes. Cook 1 minute.
Add white wine and cook until alcohol evaporates.
Add diced tomatoes with their juices, tomato sauce, oregano, basil, salt, and pepper. Simmer until sauce slightly thickens, about 10 minutes.
Meanwhile, bring water to a boil in a large pot. Cook pasta to al dente.
Mix baby spinach to tomato sauce and cook until slightly wilted. Add shrimp along with any juices that have accumulated to the sauce.
Serve over pasta.
Serve with freshly grated parmesan cheese and extra red pepper flakes, if desired.