How to Make It
In a large saucepan, heat the 1/4 cup of oil. Add the garlic, chiles and ginger and cook over moderate heat, stirring, until fragrant, 2 minutes. Add the ketchup, chile sauce, hoisin sauce, fish sauce, sugar and 1/4 cup of water. Simmer until slightly thickened, 5 minutes. Spoon 1 cup of the sauce into a bowl and let cool slightly, then stir in the scallion, cilantro, mint and tomatoes.
Light a grill or preheat a grill pan. In a large bowl, toss the shrimp with oil; season with salt and pepper. Grill over moderately high heat, turning once, until cooked through, about 6 minutes. Transfer the shrimp to a large bowl. Add the sauce from the saucepan; toss. Return the shrimp to the grill and cook, turning once, until glazed, 1 minute. Serve the shrimp with the sweet chile sauce.