To prepare marmalade, combine first 4 ingredients in a small nonaluminum saucepan. Bring to a boil; cook until reduced to 1/2 cup (about 5 minutes). Add onion and 1 teaspoon orange rind; cook 5 minutes. Sprinkle with 1/8 teaspoon salt and dash of black pepper; set aside.
To prepare sauce, combine cilantro and next 9 ingredients (cilantro through peeled garlic) in a blender or food processor; process until smooth.
To prepare couscous, bring 3/4 cup water and next 9 ingredients (water though minced garlic) to a boil in a medium saucepan; gradually stir in couscous. Remove from heat; cover and let stand for 5 minutes. Fluff with a fork.
To prepare the halibut, combine curry and 1/2 teaspoon salt. Rub the fillets with curry mixture. Lightly coat with cooking spray. Heat a large nonstick skillet over medium-high heat until hot. Add fillets, and sauté 4 minutes on each side or until fish flakes easily when tested with a fork. Place 1/2 cup salad greens on each of 4 plates, and top each serving with 1 cup couscous. Arrange fillets on top of couscous, and top with 2 tablespoons marmalade. Spoon 1/4 cup sauce around plate.