Preheat oven to 400 degrees F. Soup: Arrange squash on a sheet pan and roast until beginning to brown, about 20 minutes. In a stockpot heat oil and saute onion, ginger and garlic until onions are translucent. Add roasted squash, orange juice, chicken stock and water to cover. Bring to a boil, reduce heat and simmer until squash is tender, about 20 minutes. Using an immersion blender, puree soup until smooth. Season with salt and pepper and stir in orange zest. Crabcakes: In a large bowl mix together the crab, eggs, ginger, scallions, sherry, lemon juice and mayonnaise, mix well. Taste and season. Form mixture into 30 equal cakes. Spread the sesame seeds over a sheet pan and dip both sides of cakes just to coat them. In a large wok heat 2 cups canola oil to 350 degrees F. Add crab cakes in batches and fry for about 3 minutes on each side, turning once, or until golden brown. Serve 1 crabcake in each bowl of soup. Garnish with more orange zest.