PREHEAT OVEN TO 350F. Rinse the wild rice, and soak it in water for a half hour, then drain. Add 4 cups fresh water and salt, and bring to a boil. Cook, covered, at a simmer until the grains are swollen and tender, but still chewy, about 30 to 35 minutes. Pour the cooked rice into a colander and let it drain briefly. While the rice is cooking, toast the hazelnuts in the oven, 7 to 10 minutes, or until they smell toasty. Let them cool a few minutes; then rub them in a small kitchen towel to remove most of the skins. Don't worry about any flecks of skins that won't come off.
Roughly chop the hazelnuts, leaving the pieces fairly large. Rinse the currants in warm water and squeeze them dry; then cover them with the orange juice and let them soak until needed. Prepare the vinaigrette. Add the soaked currants and the fennel to the warm rice, and toss with the dressing. Just before serving, cut the apple into small pieces, add it to the rice, along with the hazelnuts, and toss. Season with freshly ground black pepper, and additional salt, if needed, and serve.