1In small bowl, mix hummus and goat cheese. Stir in olives. Spread 1 teaspoon hummus mixture over cut side of top half of each roll. Brush about 2 teaspoons balsamic vinegar over cut side of bottom half of each roll.
2On bottom half of each roll, layer 4 cucumber slices, 3 tomato slices, 1 onion slice, 4 bell pepper strips and 2 radicchio leaves. Cover with top halves of rolls. Insert toothpick into each sandwich. Serve immediately.