Coarsely chopped parsley or cilantro leaves for garnish.
Split the chicken in half using a pair of kitchen shears, and cutting along the side (not on) of the backbone. Start at the neck opening, cutting down towards the end at the tailbone. Lay the chicken, breast side up, in a roasting pan.
In your food processor, puree the lime zest & juice, green onions, garlic, olive oil and salt. Smear this mixture over the top of the chicken and marinade at room temperature about 30 minutes (bringing the chicken to room temperature helps ensure it will be juicy, not dry).
While the chicken is marinating, preheat oven to 400.
Lightly grease the bottom of a cast iron skillet with oil. Place chicken in the oven and them set the cast iron skillet on top of the chicken. This allows the chicken to cook evenly from both top and bottom. Bake about 45 minutes or until thoroughly cooked. Carefully remove the cast iron pan from the top of the chicken. If the chicken is not at crispy as you like, set it under the broiler for a few minutes. Garnish with parsley or cilantro leaves.