Preheat a gas grill or the broiler, or start a charcoal fire; Heat should be medium high.
Rinse the fish with wine, and let it sit for a few minutes a mixture of the wine, extra virgin olive oil, garlic, and sprigs of oregano.
Make the vinaigrette by whisking or shaking together the olive oil, most of the lemon juice, herbs, onion, salt, and pepper.
Taste and adjust the seasoning, adding more lemon juice if necessary.
Grill or broil the fish until nicely charred on each side, about 8 to 10 minutes total.
If you grill, use a fish basket or move the fish around on the grill to keep it from sticking.
If you broil, base once or twice with the pan juices.
Serve immediately, with vinaigrette.