1. Bring water and salt to rolling boil in large pot. Trim ends from asparagus and cut into 1-inch pieces. Add asparagus to boiling water and cook until tender but firm, 1 to 4 minutes, depending on thickness. Scoop out the asparagus from the pot with a sieve and rinse under cold water to stop the cooking and preserve the bright-green color. Return the cooking liquid to rolling boil. Add fresh fettuccine and cook until tender but firm.
2. Meanwhile, melt unsalted butter in large skillet over medium heat; add asparagus and cook, stirring, just to coat with butter, about 1 minute. Stir in heavy cream and grated zest of lemon, heat through. Drain pasta and add to skillet along with smoked salmon, cut into thin strips, or cooked fresh salmon, cut into small pieces, snipped fresh chives, chopped fresh parsley and salt and ground black pepper, to taste. Toss to combine and serve immediately.