Place first 6 ingredients in blender; cover. Blend on high speed until smooth. Place tofu in large resealable plastic bag or baking dish. Add 1/4 cup of the marinade; toss gently to coat well. Refrigerate 20 minutes.
Meanwhile, microwave Brussels sprouts, squash and water in medium microwavable bowl on HIGH 2 to 3 minutes or just until tender. Drain well. Thread tofu, Brussels sprouts and squash onto 8 skewers.
Broil or grill over medium heat 2 to 3 minutes per side or until lightly browned and tender, brushing occasionally with 1/4 cup of the remaining marinade. Sprinkle skewers with green onion and sesame seed. Serve with remaining marinade for dipping.