Preheat a chargrill or barbecue. To make salsa, combine tomato, onion, capsicum, coriander, garlic and olive oil in a medium bowl. Season to taste and set aside.
Season steak and grill for 2-3 minutes each side, until lightly blackened and medium-rare. Transfer to a cutting board to rest for 5 minutes. Thinly slice on diagonal and serve with salsa grilled corn cobs.