The colour (as with 'red onion') is only 'red' in so far as it isn't blue, green or yellow -- though our bean pods have the palest yellow tinge between the streaks of pink-violet (or magenta). The beans themselves are similarly streaky, though the streaks curl to match the bean shape. They also lose their colour when cooked in stock, turning an overall pale beige which deepens as the cooking continues. We are cooking them the Southern way with some hardback (suet-y) bacon in the pot. But we don't know what to do with them yet. Mashed with olive oil, garlic, and herbs, they might make a nice bean dip.
Update: What we actually did with them is make a bean-rice medley that is absolutely delicious, and will pair perfectly with the barbecued ribs and pulled pork we plan to buy for tonight's dinner. The recipe is simple: the beans were cooked, as mentioned, with the hardback bacon (which adds flavour without dissolving its fat) and a good quantity of homemade chicken stock. When the beans were done, we were left with a small bowl of rich liquid, which we topped up with water so as to cook the basmati rice. Then, in a large braising pan the jalapeños were fried in olive oil, peas were added, and both the rice and the beans were mixed in over heat. An easy dish, packed with nutrients, somehow summery and hearty at the same time. And: exceedingly moreish.