1. Place pork in a low, shallow dish or heavy-duty, zip-top plastic bag. Add 2 tablespoons orange juice, olive oil, red curry powder, and 2 tablespoons chopped cilantro. Turn to coat evenly. Marinate about 30 minutes. Place remaining 2 tablespoons orange juice, broth, and next 7 ingredients in a large saucepan, and simmer about 10 minutes.
2. Heat a large skillet over medium-high heat; remove pork from marinade, sprinkle evenly with salt, and sear pork about 2 minutes on all 4 sides. Reduce heat, and continue to cook 7 to 8 more minutes or until meat thermometer inserted into thickest portion registers 155°. Remove from skillet, cover loosely with foil, and let rest about 5 minutes.
3. Slice pork diagonally into thin strips; add to broth, and simmer about 2 minutes or until warm. Toss arugula and 1/2 cup cilantro with noodles. Divide noodles into 4 individual bowls. Spoon pork mixture over noodles, and garnish, if desired.