In a small bowl, whisk together the soy sauce, water, peanut butter, and chili paste until smooth.
Heat a large wok over medium-high heat, and add canola oil. When the oil is hot, add the garlic and ginger and let cook until fragrant, about 1 minute. Add the vegetables, chicken, and shrimp, and stir-fry until chicken and shrimp are browned and cooked through, about 2 minutes. Add noodles and toss to coat.
Add peanut/spice paste, brown sugar and cider vinegar and toss to distribute. Cook until heated through, about 2 minutes.
Spread chopped romaine on a platter. Serve pad Thai on top of lettuce and garnish with mung bean sprouts, lime, cilantro and chopped peanuts.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.