1. In large nonstick skillet coated with cooking spray, cook bread over medium-high heat for 2 to 3 minutes or until lightly toasted, turning once. Remove from skillet. Set aside.
2. Add oil to same skillet. Brush oil over skillet bottom. Add onion. Cook, covered, over medium-low heat for 15 to 18 minutes or until onion is very tender, stirring occasionally. Stir in garlic. Cook over medium heat, covered, for 4 to 6 minutes or until onion begins to brown, stirring occasionally. Remove from heat.
3. Meanwhile, cook veggie burger according to package directions.
3. Top one slice of toast with burger. Sprinkle with pepper. Add onion mixture, tomato, salad dressing and remaining toast.