Preheat oven to 350°.
To prepare spice rub, combine first 6 ingredients in a small bowl. Trim fat from veal; rub surface of veal with spice rub.
Heat oil in a large Dutch oven or large heavy stockpot over medium-high heat. Add veal; cook 3 minutes on each side. Remove from pan. Add onion, celery, diced carrot, garlic, and ginger; cover, reduce heat, and cook 10 minutes, stirring frequently. Stir in 1 teaspoon turmeric, paprika, and coriander. Add broth, wine, juice, and tomato paste, scraping pan to loosen browned bits. Return veal to pan; bring to a boil. Cover and bake at 350° for 45 minutes. Turn shanks; add squash, carrot pieces, and chick peas. Cover and bake an additional 45 minutes or until veal shreds easily with a fork. Remove veal from pan, and remove meat from bones. Serve veal and vegetable mixture over couscous. Garnish with mint, if desired.