You've never seen these on the menu at your local fast-food Mexican restaurant, and you probably never will. One of the joys of cooking is that leftovers can be used to create better meals than most people get when they eat out. These tacos are remarkably simple to make. Just put the various ingredients in their own serving containers on the table and let everyone serve themselves.
To roast and peel bell peppers: Cut off the top and bottom of the peppers and cut the peppers into fourths. Remove the seeds and ribs. Place the peppers skin-side down over a high gas flame (or under a preheated broiler, skin-side up) until the skin is black. Place in a plastic or paper bag, close it, and let sit for 10 minutes. Scrape the blackened skin off with a paring knife (don't rinse, or much of the flavor will be lost.
<a name="note2"></a>Hearts of romaine are the crisp leaves in the middle of a head of romaine lettuce.