This taco filling has all of the familiar and gratifying appeal of really good corned beef hash. Boiling the potatoes before crisping them in the skillet might seem like an annoying step that dirties an extra pot, but it’s the best way to make sure they’re tender. If you can’t find fresh chorizo, substitute finely chopped cured chorizo or use ground pork plus a couple of minced garlic cloves and a spoonful each cayenne pepper and sweet or smoked paprika. —Julia Turshen
In a large saucepan, combine the potatoes, water to cover by about 1 in [2.5 cm], and 1 Tbsp and over high heat. Bring the water to a boil, lower the heat to medium, and simmer until the potatoes are just tender, about 8 minutes. Drain the potatoes in a colander and give them a really good shake to make sure they’re as dry as possible. Let the potatoes hang out while you get the chorizo going.
Put the oil into a large nonstick skillet over high heat and crumble the chorizo into it. Cook, stirring now and then, until the chorizo has released its liquid, the liquid has evaporated, and the meat begins to sizzle in all of its glorious fat, about 8 minutes.
Add the drained potatoes and the onion and cook, stirring now and then, until everything has nice crispy edges, about 8 more minutes. Between the nonstick skillet and the fat from your chorizo, you shouldn’t need any more oil for this, but if things are looking dry and your potatoes aren’t crisping nicely, go ahead and add another splash of oil. Season the mixture to taste with salt and sprinkle with the cilantro. Serve warm.