Combine coleslaw, peppers, celery, and onion in a large bowl.
In a smaller bowl, thoroughly mash avocado flesh. Add the mayonnaise, Tabasco sauce, salt, cayenne, and milk. Stir well. You may need to add a bit more milk -- or even a bit more mayo to get a "dressing" consistency.
Pour dressing over coleslaw veggies and toss well. Cover and chill the coleslaw for at least an hour.
Remove from refrigerator, taste, and adjust seasonings as needed. Squeeze with fresh lime juice just before serving, and toss well.