Cook the rice in a large pot of salted boiling water until just tender (about 40 minutes). Drain it in a colander. Meanwhile, cut away the peel and pith from the orange. Then, while holding the oranges over a bowl to catch the juice, remove the segments from the white membrane and cut them into small pieces and place them in the bowl. Combine the vinegars, salt, and pepper in a bowl. Slowly whisk in the olive oil. In a large serving bowl, combine the rice, scallions, dried cranberries, parsley, and the orange pieces with their juice. Drizzle the vinaigrette over the top, gently toss it, and serve. For the best flavor, prepare the day before.