In a bowl, combine beef, 2 tablespoons lime juice, and 1 tablespoon
chili powder; set aside.
Heat oil in a large skillet. Add onion, bell pepper, and poblano and
saute 5 minutes, stirring occasionally.
Add beef and marinade to vegetables and cook 3 to 4 minutes.
Season with salt and black pepper.
In another bowl, combine beans, avocado, cheese, 1/4 cup cilantro,
and remaining lime juice and chili powder.
Garnish beef and vegetables with remaining cilantro. Serve with
avocado salad and warmed tortillas if desired.