Heat grill to high; lightly oil grates. Assemble four 8-inch-long presoaked wooden skewers; alternately thread zucchini, cut side down, and tomatoes. Place on a rimmed baking sheet, and drizzle with 1 tablespoon oil; season with salt and pepper. Set aside.
Place couscous in a medium bowl. Cover with 1 1/2 cups boiling water. Stir, and cover tightly with plastic wrap; let stand 5 minutes. Add 1 tablespoon oil and parsley. Season with salt and pepper, and fluff with a fork to combine. Cover again to keep warm; set aside.
Place lamb chops on baking sheet with kebabs. Rub both sides of chops with coriander; season with salt and pepper. Place chops and kebabs on grill. Cook, turning once, until chops are browned and cooked to desired doneness, 3 to 4 minutes per side (for medium rare), and vegetables are tender, 5 to 6 minutes per side. Serve chops and kebabs with couscous and, if desired, lemon wedges.