In a medium-sized pot, add rice, a big pinch of salt, and two cups of water. Bring to a boil, reduce heat, cover, and cook for 15 minutes.
Peel garlic and ginger, then mince or grate. Halve orange. Cut off and discard bulbs of bok choy. Slice stalks and leaves into 1 inch pieces. Slice scallions, keeping white and green parts separated.
In a small bowl, squeeze juice from orange. Add ponzu sauce and sweet chili sauce. Add optional red pepper flakes if you want it spicy. Whisk together and set aside.
Pat shrimp dry, then season with salt and pepper.
Heat a large pan over medium high heat with a drizzle of oil. Add bok choy, red onions, and scallion whites. Add salt and pepper to taste. Cook for three minutes then move to edges of the pan to leave a large open area to cook the shrimp.
Add shrimp to open area in the pan and cook for 2-3 minutes undisturbed. Toss together with vegetables and cook 1-2 minutes more until fully cooked.
Add ginger and garlic. Cook for 30 seconds to 1 minute until fragrant. Add sauce, stirring frequently for 2 minutes until everything is fully coated.
Serve over rice with scallion greens as garnish.