Combine first 6 ingredients in a small bowl, stirring well. Set aside.
Brush tuna with olive oil; sprinkle with salt and pepper. Grill over medium-high heat 3 minutes on each side or to desired degree of doneness. Serve immediately with olive mixture.
POUR: A glass of Chardonnay makes a fine pairing with meaty fish such as tuna. Try a full-bodied New World (think Pacific Coast) wine such as Geyser Peak. In the mood for red? Pour Calera Pinot Noir from California's Central Coast.