Heat the oil in a non-reactive saucepan. Add the onion and jalapeño and cook over moderate heat, stirring, until wilted, about 3 minutes. Add the blueberries ketchup, vinegar, sugar, mustard and hot sauce and bring to a simmer. Simmer over low heat, stirring until thickened, about 10 minutes. Puree the sauce in a blender or food processor until smooth. Pass through a Fine strainer or sieve. Taste and adjust seasoning with salt and pepper. Serve at room temperature.