In a large skillet or Dutch oven, over medium heat, add the olive oil and red onions. Sauté the onions for 4 – 5 minutes or until they are just translucent. Add the mushrooms and sauté for another 5 – 6 minutes, or until the edges just start to brown and the mushrooms have released their water. Add the garlic and cook for 1 minute. Add the two bunches of kale, oregano and chipotle, and sauté for 3 – 4 minutes, until the kale just starts to wilt. Deglaze with the beer, remove any fond from the bottom of the pan and reduce the beer to a glaze that coats the vegetables. Season with salt and malt vinegar to taste.