Cut the chorizo into small cubes. Drain, pat-dry, then finely chop the grilled pepper and sundried tomato.
Heat a frying pan and add the chorizo and oil. Gently cook until the chorizo releases its fat.
Add the peas and the chopped red pepper & tomato. Put a lid on, then sautée for 3 minutes over low heat.
Meanwhile whisk the eggs with the milk.
Pour the egg mixture over the chorizo and peas, allowing it to spread out. After a minute or so scatter the olives on top, put the lid on, and cook for about 5 minutes until the egg has just set. Add the parsley and the grated cheese. Either put the pan in the oven under the grill for a couple of minutes, or put the lid on and cook for about 3 minutes, until the cheese has melted.
Slide the omelette to a plate. Cut it into slices and serve with salad. Alternatively, let it cool, then cut it into bite-sized squares and serve as tapas.