Cook pasta according to package instructions. Reserve 1/3 cup pasta water.
Pat the salmon dry and season with paprika, garlic powder, salt, and black pepper.
Heat olive oil in a large skillet over medium-high heat. Sear salmon for 4–6 minutes per side, until golden and nearly cooked through. Remove and set aside.
Reduce heat to medium. Add butter to the same pan.
Sauté garlic until fragrant.
Add sun-dried tomatoes and red pepper flakes. Cook for 1 minute to release flavor.
Pour in heavy cream and bring to a gentle simmer, stirring often.
Stir in Parmesan cheese until melted and smooth.
Add lemon juice and mix well.
Stir in reserved pasta water to loosen and create a silky sauce.
Season sauce with salt to taste.
Return pasta to the sauce.
Add spinach and cook until just wilted.
Return salmon to the skillet and spoon sauce over the top. Simmer for 2–3 minutes, until salmon is fully cooked and coated in sauce.