Prepare Xa Xiu. Blend mayonnaise and hoisin sauce; spread rolls with mixture. Layer bottom roll halves with cucumber, jalapeno and Xa Xiu and cilantro; cover with top halves.
*Xa Xiu (Vietnamese-style "BBQ" Pork):- Combine 1/3 cup Kikkoman Hoisin Sauce, 2 Tbsp. honey and 1 Tbsp. tomato ketchup; remove and reserve 1/4 cup mixture.
- Stir 1/4 cup Kikkoman Soy Sauce into remaining mixture; pour over 2 pork tenderloins (about 1 pound each) in large plastic food storage bag. Press air out of bag; close top securely. Turn bag over several times to coat pork. Refrigerate 1 hour, turning over once.
- Bake pork on rack of broiler pan in 375°F. oven 20 minutes. Preheat broiler. Brush both sides of pork with reserved hoisin mixture.
- Broil pork on same pan 4 inches from heat source 10 minutes, until meat thermometer registers 155°, turning pork over once and brushing occasionally with remaining hoisin mixture. (Do not overcook.) Let pork stand 5 minutes; cut across grain into thin slices.
- Use to make Bahn Mi or serve over rice.
