This is a spicy marinade for the salmon. The lemon zest gives a flavorful boost to the couscous.
In a food processor, pulse cilantro, garlic, chile, ginger, paprika, and cumin until finely chopped. Add 1/4 cup oil and lemon juice and pulse to combine.
Arrange salmon in a 9-by-13-inch baking dish. Rub both sides with cilantro mixture. Cover and refrigerate 30 minutes. Preheat oven to 375 degrees. Bake salmon, uncovered, until opaque throughout, 12 to 14 minutes.
Meanwhile, in a small saucepan, bring 1 cup water to a boil. Stir in couscous, season with salt and pepper, and remove from heat. Cover and let stand until tender, about 5 minutes. Fluff with a fork and stir in lemon zest and 1 tablespoon oil. Serve salmon with couscous.