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 cooked through.
Remove salmon from the pan, let it rest briefly, then flake it into bite-sized pieces using a fork.
In the same skillet, sauté the minced garlic and baby spinach for 1-2 minutes until the spinach is just wilted.
In a small bowl, whisk together the Greek yogurt, lemon juice, lemon zest, and fresh dill to create the sauce.
Drain the pasta, reserving a splash of pasta water, and return it to the pot.
Toss the pasta with the yogurt sauce, sautéed spinach, and flaked salmon, adding reserved water if needed for creaminess.
Season with the remaining sea salt and black pepper before serving.