Heat oil in a large frying pan. Sauté pepper and onion until soft, about 5 minutes. In the mean time, place cheese, avocado and salsa in bowls.
Place meat in pan and heat until warmed through. Don't over cook meat or it will get tough.
Heat tortillas by wrapping in a damp paper towel and microwaving for 45 seconds or blister them on a grill or gas stove.
Place meat mixture and all other ingredients on a table and let everyone make their own!