Place chicken between plastic wrap, and flatten with a mallet. In bowl season flour with cayenne, salt and pepper. In separate bowl combine mustard and milk. Dip chicken in milk. Dip chicken in flour. Add oil to a large skillet and heat. Add chicken and cook until firm and golden brown, about 3 minutes per side. On plate place lettuce and onion. Add chicken. Serve with dressing on side
In small jar combine all ingredients. Shake to combine.