Cook the pasta according to the package directions. Drain and set aside.
Cut the oranges into segments, removing the surrounding membranes. Squeeze the membranes over a bowl to catch their juices.
Heat the oil in a large skillet over medium heat. Add the ginger and cook, stirring occasionally, for 2 minutes.
Sprinkle the halibut with ½ teaspoon salt, ¼ teaspoon pepper, and the cumin. Cook for 4 minutes.
Turn the halibut, add the oranges with any liquid and scallions, and cook until the fish is the same color throughout and flakes easily, 4 to 5 minutes.
Divide the pasta and fish among plates. Spoon the oranges and sauce over the top. Sprinkle with the cilantro.