Combine first 7 ingredients in a large bowl; toss well.
Spread butter onto cut sides of rolls. Heat a large nonstick skillet over medium heat. Place 6 roll halves, cut side down, in pan for 1 minute or until toasted. Repeat procedure with remaining roll halves. Spoon 1/4 cup crab mixture onto each bottom roll half. Place 1 piece of lettuce and 2 tomato slices on crab mixture; top with remaining roll halves.