Bring a large pot of salted water to a boil and cook the fettuccine according to package directions until al dente.
Season the salmon fillet with half of the sea salt and black pepper.
Heat olive oil in a non-stick skillet over medium-high heat and sear the salmon for 4-5 minutes per side until flaky and golden.
Remove the salmon from the pan, let it rest for a minute, then gently flake it into bite-sized pieces using a fork.
In the same skillet, reduce heat to medium and sauté the minced garlic and baby spinach until the greens are just wilted.
In a small bowl, whisk together the Greek yogurt, lemon juice, lemon zest, fresh dill, and remaining salt and pepper.
Drain the pasta, reserving 2 tablespoons of pasta water, and return the pasta to the pot.
Fold in the yogurt sauce, sautéed spinach, flaked salmon, and reserved pasta water, tossing gently until the noodles are coated and creamy.