Meanwhile, cook the bacon in a skillet over medium heat until crisp, about 8 minutes; remove with a slotted spoon and drain on paper towels. Remove the skillet from the heat and add the brown sugar, fish sauce, chile sauce, lime juice and lime zest to the drippings. Stir until the sugar dissolves.
Transfer the fries to a serving dish. Drizzle with the chile sauce mixture, then sprinkle with the bacon, cilantro and fried onions.