Preheat the oven to 400°F. Line a sheet pan with parchment.
Make the marinade: In a small bowl, combine olive oil, orange zest and juice, cumin, coriander, paprika, salt, and black pepper.
1 tablespoon olive oil, 1 tablespoon orange zest, ½ teaspoon ground coriander, 1 teaspoon cumin, ½ teaspoon paprika, ¼ teaspoon salt, ¼ teaspoon black pepper
Marinate the salmon: Place the salmon fillets on the prepared pan and brush generously with the marinade. Let them rest at room temperature for 10–15 minutes to absorb the flavors.
4 salmon fillets
Wash and slice the bell peppers into medium strips.
Roast the salmon: Place the pan in the oven and roast for 12–15 minutes, or until the salmon flakes easily with a fork. Thinner fillets will cook faster.
Make the gremolata: In a bowl, mix the chopped parsley, olives, garlic, lemon zest, lemon juice, and olive oil. Season to taste with salt and pepper. Stir until combined and bright green. Add red pepper flakes if you like heat.
½ cup chopped flat-leaf parsley, ⅓ cup chopped Castelvetrano olives, 1 garlic clove, Zest of 1 lemon, Juice of ½ lemon, ¼ cup olive oil, Salt + black pepper to taste, Optional: pinch of red pepper flakes
Assemble and serve: Remove the salmon from the oven. Plate and spoon the citrus-olive gremolata generously over the top. Serve immediately with roasted vegetables, rice, couscous, or a simple salad.