1. Light a grill. In a small bowl, mix the mustard, horseradish and
honey. Rub the salmon with oil and season with salt and pepper.
Grill the salmon over moderate heat, skinned side down, until
lightly browned, about 3 minutes. Turn and grill for 3 minutes
longer, until the salmon is almost cooked through. Turn the
salmon again and spread each fillet with 1 tablespoon of the
horseradish glaze. Turn and grill until glazed, about 30 seconds.
2. Spread the remaining horseradish glaze on the rolls. Place
a lettuce leaf, 2 bacon strips and 3 apple slices on each roll and
set a salmon fillet on top. Close the sandwiches and serve.