Place chicken, olive, oil, vinegar, and dry Ranch seasoning in a large slow cooker. Use your hands to toss everything together and make sure that the chicken is well coated with the seasonings. Cover and cook on LOW for 4-6 hours (or on HIGH for 2-3 hours).
Shred chicken and return meat to the slow cooker. Serve chicken in tacos (or on salad) and drizzle with buffalo sauce, blue cheese, and cilantro, if desired.
