Slice the onion half lengthwise as thinly as you can. Put the sliced onion in a bowl and cover with cold water to mellow its flavor and keep it crisp. Refrigerate for at least 15 minutes.
Working with one orange at a time, slice off both ends. Set the orange on a cutting board, one cut side down. With a sharp knife, cut away the peel (the zest and white pith) by slicing from top to bottom, following the contour of the orange. Working over a bowl to collect any juice, release the orange segments by carefully cutting them away from the membrane that separates them. Remove any seeds and put the orange segments in another bowl, separate from the juice. Squeeze the membranes over the juice bowl.
Cut the fennel in quarters lengthwise and then trim away most of the core, leaving just enough intact to keep the layers together. Slice the quarters lengthwise as thinly as you can.
With a paring knife, slice the olive flesh off the pits lengthwise. In a small bowl, whisk together the extra-virgin olive oil, lemon juice, and salt. (The recipe can be prepared up to this point several hours in advance. If working ahead, wrap and refrigerate the fennel; don’t chop the mint until just before serving.)
Drain the sliced onion and toss it with the fennel. Put the fennel and onion in a shallow salad bowl or on a rimmed serving platter. Drizzle with the reserved orange juice. Arrange the orange segments on top and sprinkle with the olives and mint.
Drizzle the dressing evenly over the salad. Add several grinds of black pepper and serve immediately.
Serve this salad with roasted or grilled seafood.
nutrition information (per serving):
8, Fat Calories
70, Saturated Fat
2, Monounsaturated Fat
13, Polyunsaturated Fat
Photo: Scott Phillips