Drain chipotle peppers, place peppers in a bowl and reserve the sauce. Slice the corned beef lengthwise into two long strips. Mix chipotle sauce with garlic and then rub all over the beef. Place beef in an oven proof pan with broth and bake in the oven for about 2 hours or until meat is tender.
While beef is cooking, toss coleslaw mixture with vinegar and a pinch of salt. Let coleslaw sit for 10 minutes and weep any liquid. While coleslaw is macerating, mince two chipotle peppers. Mix with mayonnaise, lime juice and set aside. Now drain the coleslaw mixture of excess water. Add ¾ of the chipotle mayo to coleslaw and reserve the rest.
When beef is tender, remove from oven, slice, and baste with any excess liquid from the pan.
Place tortillas on a baking sheet and warm in oven for 2 minutes.
Remove tortillas from oven, top with chipotle mayo, followed by coleslaw and finish with sliced beef. Garnish with red onions and cilantro.