Preheat broiler and position rack 1 rung from top of oven.
Bring a few inches of water to a boil in a covered deep skillet. Remove cover and season water with salt and boil the rabe 3-4 minutes to cook out their bitterness, drain well.
Place bread on a cooling rack placed over a baking sheet so heat can circulate and the bottom of the bread can remain crisp. Lightly toast bread under broiler, 2-3 minutes. Remove from oven.