Mix half the lime juice, 1/2 cup mayo, dressing mix and mustard in medium bowl until blended.
Add crabmeat, 1/2 cup cracker crumbs and onions; mix lightly.
Shape into 18 (1/2-inch-thick) patties; coat with remaining cracker crumbs.
Cook, in batches, in large nonstick skillet on medium heat 2 min. on each side or until browned on both sides and heated through. Meanwhile, mix sour cream, lime zest, remaining mayo and lime juice.