Preheat oven to 450°.
Prepare Spiced Salmon:
Place fennel and star anise in a spice or coffee grinder, and process until ground. Combine fennel mixture, ground cumin, ground red pepper, cardamom, turmeric, coriander, and cinnamon in a large zip-top plastic bag. Add salmon, and toss gently to coat. Seal bag and marinate salmon in refrigerator 1 hour, turning bag occasionally.
Prepare Harissa Vinaigrette:
Combine all ingredients in a blender; and process until smooth. Cover and set aside.
Prepare Vegetable Couscous:
Heat oil in a large nonstick skillet over medium-high heat, and add zucchini and next 4 ingredients (zucchini through onion). Sauté zucchini mixture 2 minutes or until vegetables are crisp-tender. Reserve 2 tablespoons sautéed vegetables for garnish.
Bring water and salt to a boil in a large saucepan, and gradually stir in couscous. Remove from heat, and cover; let stand 5 minutes. Fluff with a fork. Stir in remaining sautéed vegetables, tomato, olives, mint, and black pepper. Set aside; keep warm.
To complete recipe:
Remove Spiced Salmon from bag. Wipe skillet with a paper towel; wrap handle of skillet with foil. Coat pan with cooking spray; heat over medium-high heat until hot. Add salmon; sauté 4 minutes per side. Place skillet in oven; bake at 450° for 4 minutes.
Place 1 1/4 cups Vegetable Couscous on each of 6 serving plates; top with a salmon fillet and 1 teaspoon reserved sautéed vegetables. Spoon 1 tablespoon Harissa Vinaigrette and 1 tablespoon yogurt in small dollops around salmon. Garnish with shredded fresh mint leaves, if desired.
Note: Harissa Vinaigrette can be prepared in advance; cover and chill. Leftover vinaigrette may be used as a sauce for vegetables or as a condiment for meats.