"Veggie lovers can feast on this filling vegetarian appetizer or meal that can be eaten any time of the day! I fell in love with the veggie lettuce wraps at a famous Chinese chain restaurant, and put my own spin on it."
Roast peanuts in a skillet over high heat, stirring frequently until brown, reducing heat to medium if necessary, about 5 minutes; set aside to cool. In a food processor, grind peanuts into a coarse powder.
Heat canola oil in a skillet over medium heat; add tofu and season with salt to taste. Turn tofu frequently until all sides are brown, 8 to 10 minutes; remove from heat. Pat tofu dry with a paper towel and allow to cool, about 5 minutes.
Combine cucumber, radish, tomato, water chestnuts, soy sauce, and lemon juice in a large bowl. Add tofu and peanut powder just before serving.
Arrange lettuce leaves around the edge of a large platter and mound tofu filling in the center. To eat, spoon 1 or 2 tablespoons tofu mixture into the center of a leaf and wrap lettuce around filling like a burrito.