Lay chiles and bell peppers on their sides on racks of gas burners and turn flame on high. (Or broil on rack of a broiler pan about 2 inches from heat.) Roast, turning with tongs, until skins are blackened, 5 to 8 minutes.
Transfer to a bowl, then cover and let steam 10 minutes. Peel, seed, and cut into thin strips.
Whisk together dressing ingredients in a large bowl.
Dip each romaine leaf in dressing to coat, shaking off excess, and arrange on a platter. Toss pepper strips in remaining dressing and scatter over romaine.
· Peppers can be roasted 1 day ahead and chilled, covered.· You can make dressing 1 day ahead and chill, covered. Bring to room temperature before using.
