Preheat a stovetop grill pan over medium high heat.
In a small bowl, combine lemon juice, vinegar, oregano and parsley. Whisk in evoo in a slow stream. Season dressing with salt and pepper.
Transfer tubs of crab to a bowl and run fingers through the meat to check for pieces of shells. Cut the ends off 2 navel oranges. Stand oranges upright and remove peels in strips working around each orange with a sharp small knife. Thinly slice the orange, then coarsely chop. Add chopped oranges and red onion to the bowl of crab meat. Drizzle the dressing over the crab mixture and toss to evenly coat. Cover and chill salad until ready to serve.
Lightly brush the bread slices with oil and grill, turning once, until lightly toasted.
To serve, mound the chilled crab salad over the grilled bread and enjoy with a Frozen Peach Champagne Cocktail.