How to Make It
Heat 1 tablespoon oil in a large skillet over medium-high. Add shrimp, ½ teaspoon salt, and ¼ teaspoon pepper. Cook shrimp, stirring occasionally, until opaque and cooked through, 2 to 3 minutes. Transfer to a medium bowl; set aside.
Stir together vinegar and shallot in a medium bowl; let stand 10 minutes. Add olives, chives, mustard, and remaining 5 tablespoons oil, ½ teaspoon salt, and ¼￼ teaspoon pepper; whisk to combine.
Arrange escarole, endive, shaved fennel, and shrimp on a serving platter. Spoon dressing over top and garnish with fennel fronds.