Cut off the stem ends of the tomatoes and discard. Using a paring knife, remove the seeds and discard; place the tomatoes cut side down on paper towels to drain.
Meanwhile, in a heavy skillet, over medium heat, cook the bacon until crisp. Drain on a paper-towel-lined plate, then finely chop.
Stir together the mayonnaise and chipotle and spoon into a resealable bag. Cut off the tip of one corner.
Place the tomatoes cut side up on a platter and press some romaine inside each tomato; sprinkle with salt. Pipe some chipotle mayo over the romaine and top with bacon.