In a small bowl, combine the olive oil, lime juice, garlic, salt and red pepper flakes. Whisk until blended. Pour the dressing over the leaves and gently massage the dressing into the leaves until they are all lightly coated. Take a little bite, and add more lime juice and salt if you find it too bitter.
First, prepare the broccoli rabe so it can marinate while you prepare the rest. Pull the broccoli rabe leaves from the stems and discard the stems. Wash and spin dry the leaves. Tear any large leaves into small, bite-sized pieces, then transfer the leaves to a large serving bowl, along with the chopped cilantro.