In a small saucepan, heat 1 teaspoon oil over medium. Add scallion whites, season with salt and pepper, and cook until softened, about 2 minutes. Add rice and 1/3 cup water and bring to a boil. Cover and reduce to a simmer; cook until rice is tender, about 15 minutes. Remove from heat; let stand 5 minutes.
Meanwhile, combine soy sauce, lime juice, sugar, and chile. In a small nonstick skillet, heat 2 teaspoons oil over medium-high. Add shrimp and cook until opaque throughout, 2 to 3 minutes. Fluff rice with a fork and top with scallion greens and cilantro. Serve shrimp with scallion rice and soy-lime sauce for dipping.
Use kitchen shears to cut through the shell along the back of each shrimp, then peel and devein. If you don't have a jalapeno or serrano chile on hand for the soy-lime sauce, you can use a pinch of red-pepper flakes instead.