How to Make It
Cook the pasta according to the package directions. Reserve ¼ cup of the cooking water; drain the pasta and return it to the pot.
Meanwhile, heat the oil in a nonstick skillet over medium-high heat. Add the leeks, season with ¼ teaspoon each salt and pepper, and cook until beginning to soften, 3 to 5 minutes.
Push the leeks to one side of the pan. Add the salmon, cover, and cook until opaque throughout, 2 to 5 minutes per side. Flake the salmon and toss with the pasta, spinach, olives, lemon juice, and pasta water.