Preheat an indoor grill or barbecue to medium-high heat. Brush tuna steaks with oil, then season with salt and pepper. Lightly oil grill if not non-stick, then grill the steaks 3-4 to more minutes per side, or until still slightly rare in the middle. (If you like your tuna entirely cooked through, cook 1-2 minutes more per side). Divide tuna steaks among plates and serve salsa alongside.