1. Combine the figs, orange juice, and fennel seeds in a small saucepan and heat to a boil. Cook, covered, over low heat until the figs are soft and the juice is reduced to 2 tablespoons, 20 to 25 minutes. Transfer to a bowl and refrigerate until chilled. This step can be done 1 or 2 days before serving.
2. Cut the fennel in half lengthwise; place the halves cut side down, and slice into thin half circles. Finely chop 2 tablespoons of the fernlike fronds and reserve them. Place the fennel slices in a bowl of iced water and let stand for at least 20 minutes. Then drain and blot dry.
3. Grate ½ teaspoon zest from one of the oranges, and set it aside. Cut the peel and the white pith from the oranges. Working over a bowl to catch the juice, cut between the membranes with a small sharp knife to release the segments.
4. In a large bowl, combine 2 tablespoons of the fresh orange juice (reserve the remainder for another use) and the 2 tablespoons reserved fig juices with the olive oil, vinegar, garlic, salt, a grinding of pepper, and the reserved grated zest; whisk to blend.
5. Gently toss the orange segments, minced onion, and reserved fennel fronds together in a medium bowl. Drizzle with 1 tablespoon of the dressing and set aside.
6. Add the salad greens and the fennel slices to the dressing and toss to coat.
7. Divide the salad among 4 salad plates. Spoon the orange and onion mixture over the salad greens. Halve the figs and distribute them evenly among the plates. Garnish with the onion rings, and serve.