- Rinse tofu and drain in a colander for 5 minutes, then pat dry with paper towels. 
- Cut tofu into 1-inch cubes and lightly blot with more paper towels. 
- In a bowl, mix soy sauce, lime juice, chili powder, cumin, garlic powder and cayenne. 
- Add tofu cubes and mix gently to coat completely. Let stand 5-10 minutes, stirring occasionally. 
- Meanwhile, mix lettuce with seasoned rice vinegar in another bowl. 
- Thread marinated tofu cubes equally onto four 8-inch wooden skewers. 
- Heat a 12-inch nonstick frying pan over medium-high heat. 
- Cook skewers in hot pan, turning as needed to brown tofu on all sides, 5-6 minutes total. 
- Stack tortillas and wrap in plastic wrap. Microwave at full power until hot and steamy, 30-45 seconds. 
- Serve tofu, lettuce mixture, warm tortillas, salsa, and sour cream taco-style.