This lovely potatoes rioja-style with chorizo recipe is courtesy of Jose Andres and can be found in "Tapas: A Taste of Spain in America."
In a large skillet, heat olive oil over low heat. Add garlic and cook until lightly browned, about 1 minute.
Add onion and cook, stirring occasionally, until soft and caramelized, about 20 minutes. If onion begins to brown too quickly, add 1 1/2 teaspoons water to pan to keep onion from burning.
Add chorizo and cook until browned, about 2 minutes. Add potatoes and stir to coat; cook for 10 minutes.
Add pimenton and enough water to cover; increase heat to medium-high and bring to a boil. Reduce heat to low and let simmer until potatoes are cooked through and water is reduced by half, about 30 minutes. Serve immediately.