Step 1: Preheat the broiler. Put the chicken between 2 sheets of waxed paper and pound with a mallet or hammer so the chicken is an even thickness of about 3/4-inch, then cut the chicken crosswise into 1/2-inch strips.
Step 2: In a large bowl, combine the hot sauce and the oil, add chicken and toss until the chicken is well coated. Arrange the chicken on a baking sheet and broil until it is cooked through, about 4 to 6 minutes, turning once.
Step 3: In a large bowl combine the Romaine, celery, shredded carrots and scallions. Toss with the dressing. Divide the greens between 4 plates, top with the chicken.
Step 4: Serve with extra hot sauce.
Step 5: Blue Cheese Dressing : Fold a full sheet of paper towel into quarters and put it into a small bowl. Spoon the yogurt onto the paper towel and place in the refrigerator for 20 minutes to drain and thicken.
Step 6: In a medium bowl, whisk the buttermilk and thickened yogurt into the mayonnaise until smooth. Add the vinegar and sugar and continue to whisk until all the ingredients are well combined.
Step 7: Stir in the blue cheese and season, to taste, with salt and pepper.