Pat the salmon fillets dry with a paper towel and season with salt and pepper.
Spread 1 teaspoon of Dijon mustard on top of each fillet.
Press the prepared pistachio mixture onto the top of each fillet, ensuring an even crust.
Place the salmon on the lined baking sheet and bake for 10-12 minutes, or until the salmon flakes easily with a fork and the crust is golden brown.
Bring a pot of salted water to a boil. Add the asparagus and blanch for 1-2 minutes until bright green and slightly tender. Transfer to an ice bath to stop the cooking, then drain and pat dry.
In a large bowl, combine the spinach, blanched asparagus, cherry tomatoes, red onion, feta cheese, and sliced almonds. Drizzle with the prepared dressing and toss to coat evenly.
Plate the baked salmon fillets and serve alongside the asparagus spinach salad. Garnish with extra parsley or lemon wedges if desired.