Mash garlic and salt into a paste with the flat side of a chef's knife. Transfer to a mixing bowl and add vinegar and sugar, stirring to dissolve. Add carrots, onions and chiles; toss to coat.
Slice baguette into 4 equal lengths. Split each piece horizontally. Spread the cut sides with mayonnaise. Arrange the meat on the 4 bottom halves. Sprinkle with lime juice and five-spice powder. Top with the carrot salad and cilantro leaves. Cover with the bread tops.