Begin by preparing the citrus fruits. Over a bowl to catch the juices, slice off the top and bottom of each orange and grapefruit. Stand the fruit on one end and carefully slice away the peel and white pith, following the curve of the fruit.
Working over the bowl to catch any additional juices, cut between the membranes to release the citrus segments into the bowl. Once all the segments are extracted, squeeze the remaining membranes to get every last drop of juice.
In a separate small bowl, whisk together the extra virgin olive oil, white wine vinegar, Dijon mustard, honey, salt, and pepper to create a vibrant dressing.
Arrange the citrus segments on a serving platter. Scatter the thinly sliced red onion and mixed olives over the top.
Drizzle the dressing evenly over the salad, ensuring each segment gets a taste of the dressing.
Garnish the salad with the chopped mint leaves, adding a refreshing herbal note to the dish.
Serve immediately to enjoy the salad at its freshest, or cover and refrigerate for up to an hour to allow the flavors to meld.