Cut 4 of the green onions into 1-inch pieces. Thinly slice remaining 2 green onions; set aside. Juice 1 lime, cut remaining lime into wedges.
In a large pot cook pasta according to package directions; drain. Toss with 1 teaspoon peanut oil; set aside.
In a large skillet heat remaining 4 teaspoons peanut oil over medium-high heat. Add the sugar and garlic; cook and stir 30 seconds. Add tofu. Cook until lightly browned, about 8 minutes, stirring occasionally. Stir in lime juice, fish sauce and Sriracha sauce (if using). Remove from pan and set aside.
Add mushrooms to the same skillet. Cook, uncovered, over medium-high heat about 5 minutes or until mushrooms are beginning to brown. Stir in the cabbage; cook about 3 minutes or until cabbage has softened. Add the tofu mixture, noodles and 1-inch pieces of green onions; cook and stir until heated through. Top with cilantro, thinly sliced green onions and peanuts. Serve with remaining lime wedges.
Tip: If using sugar substitute, choose Splenda® Sugar Blend. Follow package directions to use product that's equivalent to 1 tablespoon sugar. Nutrition per Serving with Substitute: same as below, except: 270 calories, 33 g carbohydrate, 7 g total sugar.