Our grilling time is for pencil-thin asparagus; increase the time for thicker spears.
Snap off and discard tough ends of asparagus.
Combine olive oil, balsamic vinegar, salt, and pepper in a shallow dish or large zip-top plastic bag; add asparagus, turning to coat.
Remove asparagus from oil mixture.
Grill asparagus, covered with grill lid, over medium-high heat (350° to 400°) 2 to 4 minutes or until tender, turning once. Remove asparagus, and sprinkle evenly with grated lemon rind; serve immediately.