Sous vide salmon pieces for 1 hour at 46C/115F
Bring salted water to a boil. Cook pasta until al dente according to package instructions.
Drain the pasta, saving some pasta water.
Put olive oil in the pan on medium-low heat. Once hot, sauté shrimp shells until fragrant, then discard the shells.
In the same pan, add dried chili flakes and garlic and sweat briefly, until aromatic. Switch off the heat.
Add the pasta, pasta water, lemon juice and herbs. Stir until well combined.
Top pasta with the salmon, and lightly torch the salmon skin.
Garnish with more herbs and lemon juice. Serve hot.