Place prawns and its listed ingredients in a bowl and gently toss to combine. Marinate 30 minutes; then thread prawns and peppers on 2 skewers and set aside. Preheat grill to medium-high. Brush the steaks with olive oil, and then sprinkle with crushed peppercorns and salt, gently pressing them on. Grill steaks 3-4 minutes per side for medium rare; cook them longer if you like them more well-done. Cook the prawn skewers 2 minutes per side, or until just cooked.