Adjust rack to middle position and heat oven to 450 degrees. Heat one tablespoon oil and couscous in medium saucepan voer medium heat stirring until grains are golden, about 5 minutes. Stir in 2 cups water and 1/4 teaspoon salt and bring to boil. Reduce heat to low, cover,and simmer until couscous is tender,9-12 minutes.
While couscous cooks, mine garlic. Whisk honey, 1/2 teaspoon vinegar, paprika and 2/3 of garlic together in small bowl. Trim chicken and cut breasts in half crosswise. Pat chicken dry with paper towels and season with salt and pepper.
Heat 1 tablespoon oil in 12 inch ovensafe skillet until just smoking. Place chicken skin side down in skillet until well browned, 6-8 minutes. Flip chicken and brush with glaze. Transfer skillet to oven and roast until done 15 to 20 minutes.
While chicken cooks, mince tarragon. Whisk remaining garlic, remaining 2 tablespoons olive oil, remaining two tablespoons vinegartarragon salt and pepper together in large bowl. Peel and grate carrots.
Transfer chicken to platter, tent with foil and let rest, reserving pan juices in skilllet. Take 1/4 cup pan juices and add to dressing bowl and whisk to combine. Measure out 1/4 cup dressing and set aside for serving.
Add spinach, cous cous, and carrots to large bowl with remaining dressing and toss to coat. Drizzle chicken with reseerved dressing and serve with cous cous salad.