Mix yogurt, mint, salt, pepper and lemon juice in bowl. Refrigerate, covered, at least 1 hour.
Heat broiler. Lightly coat broiler-pan rack with cooking spray.
Cut chicken into 3 x 1/2-inch fingers.
Mix paprika, cumin, cayenne, allspice, salt and sugar in bowl. Coat chicken fingers with spice rub.
Broil chicken, turning once, for total of 5 minutes, until no longer pink in center. Garnish. Serve with dip.