Cut the chicken breasts and legs off of the whole chicken. Remove the skin. Shred the chicken off the bone and set aside in a bowl.
In a separate bowl, dress the romaine lettuce with olive oil and vinegar. Season with salt and pepper.
To assemble the tostadas, spread 1 tablespoon refried beans onto a tostada. Top with 1/2 cup shredded rotisserie chicken. Top with the dressed romaine lettuce, tomato and avocado. Drizzle with Mexican crema and top with crumbled queso fresco. Finish with pickled jalapeno peppers if desired.