Slice salmon paper thin and set aside. Saute onions quickly in olive oil. Add stock and bring to simmer. Remove from heat and whisk in creme fraiche, chives, and season with salt and pepper. Toss sauce with cooked dill noodles and garnish with smoked salmon.
Fresh Dill Noodles:
In a mixer with the hook attachment mix all the ingredients. Remove from bowl and kneed into a ball. Wrap dough in plastic wrap and refrigerate for 2 hours.
Remove dough from cooler and roll out on floured surface until 1/4-inch thick. Roll dough through pasta machine on its thinnest setting. Cut into thin strips and then cook in boiling salted water until al dente (about 2 minutes).