Preheat a large skillet over medium heat. Spray with cooking spray. Add the onion and cook until soft (about 3-4 minutes).
Add the tomatoes, oranges, orange zest, salt, pepper, and ginger. Add spices to taste; I used a dash each of salt and pepper and a few dashes of the ginger. Cook together for about 10 minutes.
Season the swai with salt and pepper. Add to the pan with the sauce and cook until the fish is cooked through (it will flake easily with a fork).
