Combine soy sauce and tofu in a small bowl. Combine mushrooms and next 5 ingredients (mushrooms through ginger) in a medium bowl.
Heat the oil in a large nonstick skillet over medium-high heat. Add vegetables; stir-fry for 3 minutes. Add tofu; stir-fry 1 minute. Stir in hoisin sauce and crushed red pepper; stir-fry for 1 minute or until vegetables are crisp-tender.
Stack tortillas; wrap in damp paper towels, and microwave at high for 25 seconds. Spread 1 1/2 teaspoons plum sauce over each tortilla. Top each tortilla with about 1/3 cup tofu mixture; roll up.