Trim some of the excess fat from the perimeter of the steaks, if desired. Season the steaks generously on both sides with salt and pepper. Let sit at room temperature for 15 minutes.
Meanwhile, finely chop the onion and mince the garlic and chipotle peppers.
Turn on an exhaust fan or open a kitchen window.
Heat a large, heavy skillet over high heat. Add the oil and swirl to coat the bottom of the skillet. Add the steaks and cook undisturbed for 4 to 5 minutes or until they have formed enough of a crust on the bottom to release easily. Use tongs to turn them over and cook for 4 to 5 minutes (medium-rare) or longer for the desired degree of doneness; moisture will just begin to accumulate on the surface of the steaks when they are medium-rare. Transfer the steaks to a plate and cover loosely with aluminum foil to keep them warm.
Reduce the heat to medium; add the onion, garlic and a generous pinch of salt to the skillet. Cook for 1 to 2 minutes, stirring, until the onion and garlic have softened, then stir in the cumin and oregano. Add the beer and cook for a minute or so, using a wooden spoon to dislodge any browned bits. Add the broth, cream and chipotle peppers. Cook for 2 to 3 minutes to meld the flavors.
Carefully transfer to a blender; be sure to remove the center knob of the blender lid so steam can escape. Place a towel over the lid opening. Puree until smooth. Strain the sauce through a fine-mesh strainer and return to the skillet. Squeeze in about 1 teaspoon of juice from the lime half and add any accumulated juices from the steaks. Taste, and add seasoning or lime juice as needed.
Cut the steaks crosswise into thick slices and divide them among individual plates. Pour the sauce over and/or around the meat.