Season each salmon fillet with salt and pepper.
In a large skillet, heat the olive oil over medium-high heat. Place the salmon fillets skin-side-down and cook for 4-5 minutes until the skin is crispy. Flip the salmon and cook for another 3-4 minutes, or until salmon is cooked through but still tender in the center. Transfer the salmon to a plate and set aside.
In the same skillet, add more olive oil if necessary and sauté the minced garlic until fragrant, about 30 seconds to 1 minute. Add the sun-dried tomatoes and cherry tomatoes to the skillet. Sauté for 2-3 minutes until the tomatoes begin to soften.
Add the baby spinach and stir until it's wilted. Pour in the heavy cream, grated Parmesan cheese, and red chili flakes (if using). Stir and allow the sauce to simmer for 2-3 minutes. Add the lemon zest and lemon juice, then stir to combine.
Return the salmon fillets to the skillet, nestling them into the sauce. Allow them to simmer in the sauce for a couple of minutes to heat through.
Sprinkle the chopped basil and parsley over the salmon and sauce. Serve the Tuscan salmon hot, ensuring each plate gets a generous serving of the spinach and sun-dried tomato sauce.
