In a large non-stick skillet at medium high heat crumble the chorizo or sausage and cook until all the fat is rendered out and the sausage is fully cooked, around 5 minutes. Add the boiled diced potatoes and continue cooking for another 5 minutes season with mustard and black pepper. Depending on the saltiness of the sausage you may need a little salt or not. Taste and decide.
Brake the eggs in to a bowl and beat slightly with a fork to combine well, season with salt and pepper to taste and add to the to the sausage-potato mixture in the skillet to cook the eggs, add parsley and cook eggs until just done, fully cooked but still moist.
Heat the tortillas for at least 30 seconds on each side divide the egg mixture into the 8 flour tortillas sprinkle each with shredded cheese, roll-up like a burrito and serve immediately.
Note: if Flour tortillas are larger, say about 10 to 12 inches, you may be able to make 4 larger servings