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