Prepare grill and if using bamboo skewers soak in water 30 minutes. Shuck corn and cut crosswise into twenty-four 1-inch pieces. Cut pork into thirty-two 1-inch pieces. Thread 3 pieces corn and 4 pieces pork onto each skewer. In a small bowl whisk together 1 tablespoon vinegar, 4 1/2 teaspoons oil, red pepper flakes, and salt and divide red pepper mixture between 2 small bowls (to prevent the potential contamination caused by uncooked meat juices). Brush kebabs with red pepper mixture from 1 bowl and grill on a lightly oiled rack set 5 to 6 inches over glowing coals, turning occasionally, until pork is cooked through, 15 to 20 minutes. With a clean brush coat kebabs with red pepper mixture from other bowl. While kebabs are grilling, trim and halve green beans. Cut potatoes into 1/8-inch-thick slices and finely chop rosemary. In a steamer arrange potatoes and layer green beans on top. Steam potatoes and green beans over boiling water, covered, until potatoes are tender, 6 to 8 minutes. In a large bowl whisk together remaining tablespoon vinegar, remaining 2 teaspoons oil, rosemary, garlic, and salt and pepper to taste. Add hot vegetables and toss to combine. Serve kebabs with vegetables.