Combine beans and enough cold water to cover generously in a saucepan. Bring to the boil and cook over high heat until tender (10-15 minutes). Drain and keep warm.
For piquillo chimichurri, place ingredients in a bowl, pour over beans and toss to combine. Season to taste, set aside.
Preheat oven to 220C. Heat an ovenproof frying pan over high heat, add chorizo and oil and cook, turning regularly, until golden (1-2 minutes). Transfer to oven and bake, turning occasionally, until heated through (5-10 minutes). Divide beans among plates, top with thickly sliced chorizo and serve immediately.
Note Piquillo peppers are wood-fired Spanish peppers available from Spanish delis and specialty food stores. The Australian versions in jars don’t have as authentic a flavour.