In a small skillet over medium heat, add the vegetable oil. When the oil shimmers in the pan, it should be up to temperature, then add the curry paste, and cook for 30 seconds, breaking it up in the pan with a wooden spoon, and mixing with the oil to cook for a bit. Then add the peanut butter, and mix thoroughly, cooking for about 30 seconds more. Add the salt, sugar, coconut milk, and rice wine vinegar. Cook for 2 minutes, whisking to thoroughly combine.