Preheat your oven to 400°F.
Rinse the asparagus and trim the woody ends.
Place the asparagus on a baking sheet lined with parchment paper, drizzle with olive oil, and season lightly with salt and pepper.
Roast the asparagus in the preheated oven for about 10-12 minutes until tender and slightly crispy.
Meanwhile, pat the salmon fillet dry with a paper towel and season both sides with a pinch of salt and pepper.
Place the crushed pistachios in a shallow dish. Brush the top of the salmon with lemon juice to help the pistachios adhere.
Press the salmon, pistachio side down, into the crushed pistachios to form a crust.
Heat a non-stick skillet over medium-high heat. Carefully place the salmon in the pan, pistachio crust side down, and cook for about 3 minutes until the crust is golden.
Flip the salmon and continue cooking for an additional 3-4 minutes or until the salmon is just cooked through.
Plate the salmon with the roasted asparagus on the side, squeeze additional lemon juice if desired, and serve immediately.