How to Make It
In a shallow bowl or baking dish, combine the pineapple juice, soy sauce, and ½ teaspoon pepper. Add the steak and turn to coat. Let marinate for at least 30 minutes.
Meanwhile, fill a large saucepan with 1 inch of water and fit with a steamer basket; bring the water to a boil. Place the potatoes in the basket, cover, and steam until tender, 12 to 14 minutes, adding the green beans after 6 minutes; drain. In a large bowl, toss the potatoes and green beans with the chilies, oil, vinegar, cumin, ½ teaspoon salt, and ¼ teaspoon pepper.
Heat grill to medium-high. Remove the steak from the marinade (discard the marinade) and grill, 4 to 6 minutes per side for medium-rare. Let rest for at least 5 minutes before slicing. Serve with the potatoes and beans, sprinkled with the cilantro.