Cut the chorizo into small cubes and fry them in a dry skillet over medium heat for two to three minutes until the orange fat is released and the cubes are crispy. Remove them from the pan with a slotted spoon, leaving the fat behind; this is the flavor base for the rest of the dish.
Dice the tomato, removing the watery seeds. Fry the diced tomato in the chorizo fat for one minute, then transfer to the plate with the chorizo. Do not overcrowd the pan: tomatoes cooked for too long release moisture, and scrambled eggs in a wet pan will turn grainy instead of creamy.
Whisk the eggs with salt, pepper, and the smoked paprika. Lower the heat, add the butter to the pan, and pour in the eggs as soon as the butter has melted. Stir slowly and continuously with a spatula across the bottom of the pan, and remove from the heat while the eggs are still slightly glossy; they will continue to cook on the plate.
Fold the chorizo and tomato into the scrambled eggs. Finish with the finely sliced green onion, plenty of parsley, and a grind of black pepper.