Spanish Salad of Oranges, Fennel, Red Onion, and Mint with Dressing

"This is a typical Spanish-style salad, but it goes well with almost any menu." - Lillian Julow, Gainesville, FL
Place the thinly sliced red onion in a medium bowl; cover with ice water and let stand for 15 minutes. Strain well.Carefully remove the peel and white core from the oranges; discard the peel and core. Cut each orange vertically in half; remove the white core and discard. Slice the oranges crosswise into 1/4-inch thick slices, reserving about 1/3 cup of juice for dressing.Place the red onion, thinly sliced fennel, and orange evenly in a bowl or platter and sprinkle with fresh mint leaves. Combine the remaining juice, plain low-fat yogurt, juice concentrate, and other ingredients in a small bowl and whisk together. Pour evenly over the salad; serve immediately.