Slice each breast lengthwise into thirds, for a total of 6 portions. Place duck in a plastic bag or sealable container and add teriyaki sauce; shake to completely cover meat. marinate for at least one hour.
Remove duck from marinade and lay out flat on a working surface. Cover each portion with 1⁄2 slice of cooked ham and place one or two jalapeno slices in the centre. roll up combination, using round toothpicks to hold together.
Preheat barbecue to 350°F. Place poppers on grill for approximately 8 minutes or until duck is cooked medium, turning once.