Bring a medium to large sauce pot of water to a boil. Add salt and pasta and follow package instructions until is al dente; and drain. Reserve about 1/3-1/2 cup of the pasta water.
Season salmon and shrimp with salt and pepper. In a large skillet, over medium-high heat, melt butter, and sear salmon for about 4-5 minutes on each side and shrimp 2-3 minutes on each side. Then remove and set aside on a plate, cover with foil.
Using the same skillet, on medium heat, add olive oil, then add onions, and sauté for about 3 minutes until softened. Add garlic and diced peppers and cook for 1 minute. Stir in the tomato paste and add grape tomatoes, cook for 1 minute. Then add pasta water, cream, basil and oregano. Cook for about 3-4 minutes until sauce starts to thicken. If the sauce is too thick add some pasta water. Drop in the spinach, red pepper flake if using and season with salt and pepper. Remove the skin of salmon and separate it into pieces and add to skillet along with the shrimp. Simmer for 2-3 minutes until the salmon and shrimp have heated through.
Garnish with fresh parsley and fresh basil. Serve with pasta and enjoy!
