Preheat broiler to high. Broil the poblanos with the oven door ajar to allow steam to escape to char them all over. Place chilies in a bowl, cover and let cool. Peel and seed, and purée in a food processor.
Meanwhile, season the red onion rings with half of the lime juice, salt, pepper and a little EVOO to coat. In a second bowl, mash together the avocado, sour cream, cilantro, Fresno chili and remaining lime juice. Season to taste with salt.
In a large bowl, combine the beef, pork, puréed Poblano, cumin, coriander, paprika, cinnamon, salt and lots of pepper. Mix in the beer and Worcestershire. Form the mixture into eight 3-inch patties (a little thinner in the center and thicker at the edges).