1. Place tofu on paper towels; cover with paper towels. Top with a heavy skillet; let stand 20 minutes. Cut tofu crosswise into 8 (1/2-inch-thick) slices.
2. Combine ketchup and next 6 ingredients in a saucepan; bring to a boil. Reduce heat to medium-low; cook until reduced to 1 cup (12 minutes), stirring occasionally. Set aside 1/2 cup.
3. Preheat grill to medium-high heat.
4. Brush oil over tofu and eggplant; sprinkle with salt. Place eggplant on grill rack coated with cooking spray, and grill 2 minutes. Turn eggplant over, and brush with 2 tablespoons sauce; grill 2 minutes. Turn eggplant over; brush with 2 tablespoon sauce. Cook 2 minutes on each side.
5. Add tofu to grill; grill 3 minutes. Turn tofu over, and brush with 2 tablespoons sauce; grill 3 minutes. Turn tofu over and brush with 2 tablespoons sauce; grill for 1 minute on each side. Sprinkle with onions and seeds. Serve with eggplant and 1/2 cup reserved sauce.