Preheat oven to 400°F. Line a sheet pan with aluminum foil. Set aside.
Cook the pasta according to package directions in a pot of generously salted water. Once ready, reserve about cup of pasta water for later. Drain and set aside.
Prep salmon and tomatoes: Place the salmon (skin-on is fine, it will come off later) on the prepared sheet pan. Season salmon with about 1 tablespoon of olive oil, ½ teaspoon salt and ¼ teaspoon ground black pepper. On the same sheet pan, arrange the cherry tomatoes and drizzle with olive oil and a pinch of salt and pepper.
Roast salmon and tomatoes: Roast both for 10-12 minutes, or until the salmon is fully cooked and the tomatoes are a bit blistered (press them lightly if needed). Remove from oven and let it rest for a few minutes. Using a fork, roughly flake the salmon with a fork, and discard the skin. Set aside.
Make the creamy sauce: Meanwhile, melt butter on a large skillet and add the minced garlic over medium heat. Saute for 1-2 minutes or until fragrant. Then, add the heavy cream and bring to a very light simmer. Next, stir in freshly grated parmesan cheese and a few grinds of black pepper, and simmer gently until thickened.
Toss pasta with sauce: Toss the cooked fettuccine into the sauce, adding a splash of reserved pasta water as needed to adjust the consistency (you will not need all the pasta water). Stir in the spinach to incorporate.
Bring everything together: Add the cooked salmon and tomatoes, and fold them in to combine. Garnish with grated parmesan cheese. Serve immediately. Enjoy!