Grill or pan-fry the sausages over medium heat until fully cooked and browned on all sides. Set aside to rest.
In a small saucepan, heat the oil over medium heat. Add the chopped onion and sauté until translucent.
Stir in the tomato paste and cook for 1-2 minutes.
Add ketchup, Worcestershire sauce, curry powder, paprika, cayenne (if using), water, salt, and pepper.
Simmer the sauce for 5-10 minutes, stirring occasionally, until slightly thickened.
Slice the sausages into bite-sized pieces and pour the warm curry sauce over them.
Sprinkle with additional curry powder and serve with fries or crusty bread.