1/2 cup soy sauce 2 shallots, 1/2 inch diced 1 tablespoon fresh ginger, minced 1/2 cup hoisen sauce 1 cup water 1/2 cup rice wine vinegar 2.5-pound slab of pork belly or boneless pork shoulder picnic 2 carrots, peeled and shredded 1 bunch scallions halved lengthwise 20 6-inch Chinese crepes or flour tortilla |