Place chicken breast halves and half of dressing in a large zip-top plastic bag; seal and chill 2 hours, turning occasionally.
Snap off tough ends of asparagus; remove scales with a vegetable peeler, if desired. Place asparagus and remaining dressing in a zip-top plastic bag; seal and chill 2 hours, turning occasionally.
Prepare hollandaise sauce according to package directions, and set aside.
Remove chicken and asparagus from dressing, discarding dressing.
Cook chicken, asparagus, and Canadian bacon, without grill lid, over medium-hot coals (350° to 400°) about 5 minutes. Remove asparagus and Canadian bacon, and keep warm. Turn chicken, and cook 5 more minutes or until done. Cut chicken into thin slices, and keep warm.
Place Canadian bacon on bagels; top evenly with chicken, asparagus, and hollandaise sauce. Sprinkle with cheese, and serve immediately.
*1 (15-ounce) can asparagus spears, drained, may be substituted; do not grill the asparagus.