Heat oil in a large skillet over medium heat. Cook the onions, ginger and garlic for 5 minutes or until fragrant.
Add the red peppers and tofu and cook for an additional 10 minutes, stirring occasionally. Add the zucchini noodles for the last minute.
Meanwhile, bring a medium pot of water to a boil and cook the noodles according to package's instructions.
Prepare the peanut sauce: In a jar or small bowl, whisk together the peanut butter and vinegar. Thin it out with soy sauce and water.
Add the cooked noodles and peanut sauce to the skillet with cooked vegetables and tofu. Stir together until evenly coated with sauce. Serve with purple cabbage, green onions, peanuts, cilantro and a drizzle of lime juice if desired.