Wash lettuce leaves under cold water and dry with a paper towel. Alternatively, dry on a clean kitchen towel..
To make the stir-fry sauce, combine coconut aminos (or low-sodium soy sauce), white rice vinegar, maple syrup, minced ginger, and garlic in a bowl. Mix it with a whisk or fork till well-mixed.
In a separate bowl, add tofu, half of the cayenne pepper, and half of stir-fry sauce. Heat 1 tsp of oil in an iron skillet (or any other type) on medium heat. Add tofu and cook it until brown. It does not have to be perfectly brown on all sides. Don't let it brown for too long; otherwise, it may become hard.
While the tofu is browning, add 1 tsp of oil to a separate pan on medium heat. A tapered Chinese stir-fry pan works great, but any other type also works.
Add onion and cook for 2 minutes or until soft. Add garlic and ginger and cook for a minute. Add finely chopped mushrooms and add a pinch of salt. Cook, stirring often, till mushrooms are soft. Add finely chopped jicama (or water chestnuts). Cook for another 2 minutes. I like jicama to have a bite to it, but if you like it soft, you can cook longer.
Add stir-fried tofu to this mixture and add the remaining stir-fry sauce. Mix well for about a minute. Add cilantro and mix.
Cool the mixture till it comes to room temperature. Once cooled, serve with lettuce wrap and sweet and sour sauce. Enjoy!