1. Place shallot in 2 cups ice water and let stand for 30 minutes. Drain and pat dry with paper towel.

2. Remove 1 teaspoon finely grated zest from 1 orange. Cut thin slice from tops and bottoms of oranges. Stand oranges on ends and slice away rinds and white pith. Quarter peeled oranges lengthwise, then cut crosswise into 1/4-inch pieces.

3. Whisk vinegar, paprika, mayonnaise, orange zest, and 1/4 teaspoon salt in nonreactive bowl until mixture appears milky and no lumps remain. Whisking constantly, slowly drizzle in oil. (Dressing should appear homogeneous, glossy, and slightly thickened, without any pools of oil on surface.)

4. Gently toss avocados, 2 tablespoons dressing, and 1/2 teaspoon salt in bowl. Transfer avocados to large platter or individual plates.

5. Toss shallot, orange pieces, fennel, almonds, parsley, and olives with remaining dressing. Spoon orange mixture over avocados. Serve immediately.

Serves 6