Bring a large pot of water to boil and cook the bow tie pasta according to package directions until al dente.
When noodles are done cooking, use a slotted spoon to transfer the pasta to a colander, reserving the pasta cooking water in the pot.
Reheat the pot of water over medium heat and add the chopped asparagus spears, cooking until they turn bright green, about 1 to 2 minutes, then transfer to the same colander as the pasta.
While the pasta and asparagus are cooking, pour the cream into a 12-inch skillet and bring to a boil, then reduce to simmer and cook until reduced by half and the cream easily coats the back of a spoon.
Add the lemon zest, Parmesan cheese, fresh dill and cooked salmon to the cream and stir until the Parmesan is melted into the cream and the salmon is warmed through. Season with Kosher salt and freshly ground pepper.
Add the cooked bow tie pasta to the skillet and toss to coat. Add more salt and pepper if desired, and top with more Parmesan cheese and dill if desired. Serve immediately.
