Poach the shrimp
In a mixing bowl, toss the shrimp with the orange zest, ginger, pepper flakes, and 3/4 tsp. salt. Let sit at room temperature for about an hour.
Position a rack in the center of the oven and heat the oven to 225°F.
Pour 1 inch of oil into a medium (10-inch) straight-sided sauté pan. Heat over low heat until the oil reaches 120°F, 2 to 3 minutes.
Slide the shrimp into the oil and immediately transfer the pan to the oven. Poach until the shrimp are opaque throughout (cut into one to check), 25 minutes. With a slotted spoon, transfer to a wire rack and blot on both sides with paper towels to remove excess oil.
Make the sauce
While the shrimp poach, heat the oil in a medium skillet over medium-high heat. Add the onion and a pinch of salt. Cook, stirring frequently, until soft and translucent, about 4 minutes. Add the garlic, ginger, and orange zest and cook, stirring, until fragrant, 1 minute more. Add the tomatoes and their juices, orange juice, and sugar and simmer for 5 minutes to meld the flavors. Purée the sauce in a food processor. Return to the pan, season to taste with salt, and keep warm over low heat until the shrimp are ready. Distribute the tomato sauce among 4 serving plates, arrange the shrimp on top of the sauce, and serve.
nutrition information (per serving):
Photo: Scott Phillips