01 - Cut the tofu into 8 thin slices.
02 - In a shallow dish, whisk together soy sauce, olive oil, maple syrup, smoked paprika, liquid smoke, garlic powder, onion powder, and black pepper.
03 - Add tofu slices to the marinade, turning to coat. Let marinate for at least 15 minutes, turning once.
04 - Heat a nonstick skillet or grill pan over medium heat. Add tofu slices and cook for 3-4 minutes per side, until golden and slightly crispy. Remove from heat.
05 - Toast bread slices if desired. Spread vegan mayo on one side of each slice.
06 - Layer on each sandwich: lettuce leaves, tomato slices, smoky tofu, and red onion if using. Top with remaining bread slices.
07 - Slice sandwiches in half and serve immediately.