Season the salmon with salt and pepper. Place in a large baking dish with 1 cup orange juice. Cover with plastic wrap, and marinate in refrigerator, for at least 1 and up to 2 hours.
Preheat oven to 425 degrees. Finely chop pistachios and zest in food processor. With the processor running, drizzle in oil and remaining 1 cup juice until a paste forms; set aside.
Lightly coat a rimmed baking sheet with cooking spray. Place salmon on baking sheet; discard excess marinade. Top with pistachio mixture, pressing lightly to adhere.
Bake until salmon is cooked through and pistachios are golden, 20 to 25 minutes. Garnish with zest, if desired. Serve immediately.