Marinate the shrimp : In a large bowl, mix the vegetable oil with the parsley, garlic, basil, ginger, lemon juice, salt and crushed red pepper. Add the shrimp and toss to coat. Cover and refrigerate for at least 2 hours and up to 4 hours.
Meanwhile, make the sauce : In a medium saucepan, heat the vegetable oil. Stir in the ginger, garlic and lemongrass and cook over moderate heat until fragrant, about 2 minutes. Add the tomatoes and cook over moderate heat, stirring occasionally, until slightly thickened, about 10 minutes. Let cool to room temperature, then stir in the lime juice and cilantro. Season with salt. Transfer the sauce to ramekins.
Light a grill. Loosely thread the shrimp onto 10 skewers. Grill over moderately high heat, turning once, until lightly charred and cooked through, about 5 minutes. Transfer the shrimp to plates and serve with the tomato sauce.