In a resalable plastic bag stir together the lime juice, orange juice, Slow Roasted Garlic, cumin, 1 teaspoon salt and ½ teaspoon pepper. Add the steak and marinate at least 1 hour and up to one day.
Heat your oven to 375. Cut the ends of the plantains and score the peel from end to end lengthwise. Peel by unwrapping, starting where you scored. Slice the plantains on the diagonal into half inch slices.
Place on a parchment lined baking sheet and toss with ¼ cup Zesty Ranch. Spread in a single layer and bake until golden brown on the bottom about 15 minutes, turn over and bake until very tender, about 15 minutes more.
While the plantains roast: Heat your grill or grill pan to medium-high. Remove the steak from the marinade and season with salt and pepper. Grill until medium rare, about 4 minutes per side. (You can grill skirt steak longer, but it gets very tough if cooked past medium.) Let the steak rest at least 5 minutes before slicing. Serve with the plantains, lettuce and avocado.