In a small bowl, combine 2 teaspoons Italian seasoning, 1 teaspoon salt, 1/2 teaspoon pepper and garlic powder. Coat salmon fillets with spice mixture.
Heat oil in a large skillet over medium heat. Add salmon, skin-side down; cook until skin is crispy, 4-5 minutes. Flip; cook another 2-3 minutes or until salmon flakes easily with a fork and an instant-read thermometer inserted into the center of a filet reaches 145°. Remove to a plate; tent with foil to keep warm.
Reduce skillet heat to medium; add butter and shallot. Cook until shallot is softened, 3-5 minutes. Add garlic and crushed red pepper flakes; cook until fragrant, 30-60 seconds. Stir in flour; cook until lightly browned, 2-3 minutes.
Slowly whisk in broth; bring to a simmer. Add sun-dried tomatoes and the remaining 2 teaspoons Italian seasoning, 1/2 teaspoon salt and 1/2 teaspoon pepper; cook until thickened, 4-5 minutes.
Stir in cream, milk, cream cheese, Parmesan, spinach and basil. Cook until the cream cheese has melted and the sauce is smooth, 2-3 minutes. Stir in cooked orzo, if using.
Return salmon to the skillet; cook until warmed through. Garnish with basil to serve.