Trim the green onions to about 6 inches in length (save the tops for another use). Cut each trimmed green onion in half width-wise. Set the onions on a plate, drizzle with 2 Tbsp. of the olive oil and set aside. Preheat your grill to medium-high. Meanwhile, place the wine in a small pot set over medium-high heat and bring to a boil. Lower heat and simmer until the wine is reduced by half, then whisk in the stock/flour mixture. Return to a boil, then reduce the heat to the lowest setting. Season the sauce with salt and pepper; cover and keep over low heat until the steaks are cooked. Brush the steaks with the remaining oil and season with salt and pepper. Grill the steaks on one side of the barbecue for 3-4 minutes per side, or a little longer if you like them cooked more than medium rare. Grill the green onions on the other side of the barbecue for about 30 seconds per side, and then divide and arrange them on 4 plates. Set the steaks on top of the green onions, spoon the sauce over the steaks and serve.