Sauce, soy sauce, dark brown sugar, and garlic powder. Season with salt and pepper.
Bring 1¾ cups water to a boil in a medium saucepan. Add the quinoa, stir, and cover. Reduce heat to medium/low and cook for 15-18 minutes, or until all liquid has been absorbed. Fluff quinoa with a fork.
Add vegetable oil to a large skillet over medium heat, swirling pan to coat the entire surface. Heat oil until slightly smoking. Arrange mandu in skillet and fry until golden brown, about 2 minutes. Turn over and fry on the other side for another 2 minutes. Remove mandus from pan and let rest on a plate lined with paper towels.
To assemble, portion quinoa into bowls and top with a scoop of the toppings. Add a handful of shredded vegetables for the toppings and a lime wedge. Place the Mandus on top before serving.
