With a vegetable peeler or paring knife, remove zest from orange, avoiding the white pith. Cut zest into 1-inch lengths. Cut orange in half, and juice it; set juice aside.
Place a large skillet over medium-high heat, and add oil. A minute later, add chilies and zest. After a minute or so, chilies will start to smoke; turn heat to high, and add shrimp. Cook without stirring for about 2 minutes, then stir shrimp, and season with salt and pepper.
Add scallions and cook, stirring occasionally, until they just begin to soften, about 2 minutes. Stir in orange juice and cook for 30 seconds. Taste, and adjust seasoning if necessary. Serve.
Notes: Don’t use a zester for the orange or tangelo, for you will want fairly large pieces of zest. Stick with a vegetable peeler or paring knife, and avoid as much of the bitter white pith as you can. Wild Pacific or white gulf shrimp, which are especially meaty and highly flavorful, are the best choice here; they will stand up well to the chilies.
