Arrange strips of skirt steak on a platter and pass warm flour tortillas, so everyone can wrap beef strips in tortillas. Serve the guacamole on the side or in the tortillas.
Set the rack in the broiler 4 inches from the heat source.
Peel the avocado and discard the seed.
Dice the avocado and place in a serving bowl.
Coarsely mash the avocado with the back of a fork.
Stir in the lemon juice, tomato, chile, scallion, 1/4 teaspoon salt and 1/8 teaspoon pepper.
Set aside.
Taking a sharp knife, score the steak.
You do this by making shallow diagonal slashes in one direction on the steak, then across in the other direction.
Smash the garlic clove with the flat of a knife.
Rub the smashed garlic over the surface of the meat.
Rub the ground cumin on both sides of the meat.
Then drizzle on the lime juice.
Sprinkle the meat with the remaining 3/4 teaspoon salt and 1/8 teaspoon pepper.
Place the meat on an oiled rack over a broiler pan 4 inches from heat and broil 3 to 5 minutes on the first side and 3 to 4 minutes on the second side.
Remove from the broiler and let stand 1 minute.
Cut the meat into thin strips crosswise and arrange on a serving plate.
Pass the guacamole separately or serve it in the tortillas.
Speed It Up!
Buy a half-pint of prepared guacamole from a deli or supermarket.