How to Make It
Combine first 5 ingredients in a medium bowl, stirring with a whisk. Add pork, turning to coat. Let stand 10 minutes.
Heat a grill pan over high heat. Coat pan with cooking spray. Arrange half of pork on pan; grill 1 1/2 minutes on each side or until done. Remove pork from pan. Repeat procedure with remaining pork. Hollow out top and bottom halves of bread, leaving a 1-inch-thick shell; reserve torn bread for another use. Combine mayonnaise and hoisin in a small bowl. Spread mayonnaise mixture evenly over top halves of bread. Arrange lettuce over bottom halves of bread; top evenly with pork, cucumber, and jalapeño. Top with top halves of bread.