To a large pot with boiling water (about 4-6 quarts water), add salt (about 1 tbsp) and the pasta, and boil for the time indicated on the package. Make sure to stir when adding the pasta and a couple of times in the beginning so the pasta doesn't stick.

While the pasta is boiling, chop the capers and finely mince the fresh chives using a chef's knife. Zest the lemon with a zester/grater and juice the lemon.

To the same (now-empty) pasta pot or to a large heatproof mixing bowl, add the ricotta, lemon juice, lemon zest, and chopped capers along with 1/2 cup of the pasta water. Mix everything well until the sauce is smooth.

Add the cooked pasta back to the pot or to the large mixing bowl, and mix with the sauce. Add more pasta water as needed to get to your preferred consistency.

Add the smoked salmon (tearing it into bite-sized pieces) and fresh chives just before serving. Toss lightly, taste, and season with salt and pepper to taste before serving.