In 1 1/2-quart slow cooker, place chicken; sprinkle with salt.
Cover; cook 6 to 7 hours (if slow cooker has heat settings, use Low).
With slotted spoon, remove chicken from slow cooker and place on cutting board; discard liquid in slow cooker. In slow cooker, mix buffalo wing sauce and 1/4 cup of the ranch dressing. With 2 forks, shred chicken. Return chicken to slow cooker; stir gently to mix with sauce.
To serve, spread each tortilla with 1 tablespoon remaining ranch dressing; top each with about 1/2 cup chicken mixture and about 1/3 cup lettuce. Roll up tortilla; secure with toothpicks.