Thaw scallops, if frozen. Rinse and pat dry with paper towels. Cut upper stalks from fennel bulbs. Remove any wilted outer layers and cut and discard a thin slice from each fennel base. Cut fennel bulbs into very thin slices.

In a large bowl, combine fennel, oranges, olives, tarragon, lemon juice, 1 tablespoon of the olive oil, and the champagne vinegar. Stir in 1/4 teaspoon of the kosher salt and 1/4 teaspoon of the pepper. Cover and let stand for 15 minutes.

Meanwhile, in a large bowl, toss scallops with remaining 1 tablespoon olive oil, 1/4 teaspoon kosher salt, and 1/4 teaspoon pepper. Thread scallops onto long skewers, leaving a 1/4-inch space between them. Grill over medium heat 5 to 8 minutes, or until scallops are opaque, turning once halfway through grilling. Divide fennel mixture among four dinner plates. Top with scallops; sprinkle with almonds. Garnish with tarragon.