Heat a large pan of water to boil for pasta. Salt the water and add pasta to cook to al dente or, with a bite to it. While pasta cooks, toast pine nuts in a small pan until golden, then cool.
Place nuts, basil, tarragon, parsley, lemon zest, garlic, cheese and a little salt and pepper in a food processor. Turn the processor on and stream in the extra-virgin olive oil until thick sauce forms.
Poach the salmon in simmering salted water with some black pepper added for 4-6 minutes.
Scrape pesto into large, shallow serving dish. Add a ladle of hot, starchy pasta water to the pesto. Drain penne and add immediately to pesto. Toss to coat the pasta and evenly. Adjust salt and pepper, to taste. Place the salmon on top of the pasta and add some black pepper to serve.