Combine first 9 ingredients in a blender, and process until smooth. Pour puréed sesame seed mixture into a large bowl; set aside. Cut each tofu cake crosswise into 4 slices. Place tofu slices in sesame seed mixture, and marinate in refrigerator at least 2 hours.
Coat a large nonstick skillet with cooking spray, and place over medium-high heat until hot. Remove tofu slices from marinade; discard marinade. Add tofu slices to skillet, and cook 2 minutes on each side or until browned. Remove from skillet; set aside, and keep warm.
Heat 1 teaspoon vegetable oil and 1 teaspoon sesame oil in skillet over medium-high heat. Add bok choy, 1 teaspoon gingerroot, and minced garlic; sauté 2 minutes. Add green onions and 1 tablespoon soy sauce; sauté 2 minutes.
Spoon bok choy mixture onto individual plates, and top with tofu slices.
