Whisk hot pepper sauce, 2 tablespoons vinegar and cayenne pepper in a medium bowl.
Shred the chicken. Add to the bowl with the hot sauce; toss to coat well.
Whisk mayonnaise, yogurt, pepper and the remaining 1 tablespoon vinegar in a small bowl. Stir in blue cheese.
Slice celery, enough to yield about 1 cup.
To assemble sandwiches toast bread, then spread with 1 tablespoon blue cheese sauce and top with one-fourth of the chicken, lettuce, celery and tomato. Drizzle with some of the hot sauce remaining in the bowl.
Serve with a half a banana.