1. Steam squash and 1/2 cup onions, covered, 15 minutes or until tender. Drain well. Mash mixture with a fork. Stir in crackers and next 3 ingredients (through eggs). Cover and chill for 3 hours; drain well in a fine mesh strainer.
2. Place cornmeal in a shallow dish. Divide squash mixture into 12 equal portions, shaping each portion into a 1/2-inch-thick patty. Lightly coat each patty with cooking spray.
3. Heat 1 teaspoon canola oil in a large nonstick skillet coated with cooking spray over medium-high heat. Place 4 patties in pan; cook 1 1/2 minutes on each side or until golden. Remove patties from pan. Repeat procedure 2 times with remaining 2 teaspoons oil and 8 patties. Garnish with onions, if desired. Serve immediately.