In a shallow baking dish, whisk together vinegar, 2 Tbsp olive oil, Moroccan spice blend, and honey. Add salmon filets to the dish and turn them to coat.
Leave salmon flesh-side down in marinade and refrigerate for 20 minutes while the oven heats.
Preheat oven to 450°F / 232°C.
While oven is heating, melt butter in a saucepan. Add carrots, zucchini, and red onion with a pinch of salt. Sauté over medium heat until carrots are very tender, 10 to 14 minutes.
Pour stock over vegetables and bring to a boil. Add ground cumin and saffron. When stock is boiling, stir in couscous and salt. Remove from heat. Cover with a lid and let sit until ready to serve (at least 10 minutes).
Remove salmon from the refrigerator.
Line a sheet pan with foil. Spray it with nonstick cooking spray or brush with some oil.
Place salmon flesh-side up on the prepared sheet pan (discard marinade). Season salmon with some salt and pepper.
Bake salmon until it flakes easily with a fork, 10 to 15 minutes (depending on thickness).
While salmon roasts, fold golden raisins and lemon juice into couscous.
Serve salmon over couscous with toasted nuts, parsley, and yogurt.