Preheat the oven to 425ºF.
Prepare tofu: Cut the block of tofu widthwise into approximately 16 (¼-inch-thick) rectangles. Lay them on paper or kitchen towel and pat dry both sides. Transfer them to a large nonstick baking sheet in a single layer.
Prepare spice paste: In a medium bowl, mix the smoked paprika, garlic powder, chipotle powder, and salt to taste. Add the olive oil and mix well until fully incorporated, adding a little water as needed to thin out the paste if it is too thick. (For oil-free, use coconut aminos instead of oil.)
Cook tofu: Use a pastry brush to coat the top and bottom of the tofu rectangles with the spice paste. Bake them for 10 minutes. Flip them over and brush with any remaining paste. Bake for about 10 minutes more, or until lightly crispy. Cut each rectangle lengthwise into about 6 (¼-inch-thick) batons.
Prepare filling: Cut the mango, cucumber, and bell pepper into matchsticks about the size of the tofu sticks.
Rice paper: Fill a large shallow dish or pie plate with about 1 inch room temperature water. Dunk one rice paper sheet into the water for 3 to 4 seconds (see packet directions), or until it is just pliable enough to roll, but still stiff.
For serving: Place some lettuce, tofu, mango, cucumber, bell pepper, and 2 to 3 mint leaves in the lower third of the rice paper (the third closest to you). Start with the lettuce, and stack the other ingredients on top, leaving at least 1 inch clear of fillings on all edges of the wrappers.
Roll: Wrap the rice paper roll much like rolling up a burrito. Pick up the rice paper wrapper from the end closest to you, pulling it over the fillings to enclose them. Then, fold both sides in towards the center. Complete by rolling the whole roll away from you. You should end up with a log shape roll with the filling completely enclosed.
Make peanut sauce: Add the peanut butter, tamari, lime juice, maple syrup, and ginger to a medium bowl. Press or grate the garlic into the bowl. Add sriracha, and warm water as needed, stirring continuously until fully incorporated. Adjust maple syrup, and lime juice to taste.