In a large glass or stainless-steel bowl, combine the fennel, chickpeas, olives, capers, parsley, garlic, and tomato. Add the vinegar, oil, salt, and pepper and toss.
Remove some of the soft center from each half roll, leaving a 1/2-inch shell. Mound the filling onto the bottom of each roll. Drizzle any remaining juices over the filling. Cover with the top of each roll.
If you have time, wrap each roll tightly in aluminum foil and let sit for 15 minutes or up to 2 hours. Otherwise, press down on the rolls firmly so that the dressing moistens the bread.