Make the tortilla bowls: Position a rack in the lower third of the oven; preheat to 450 degrees F. Put 4 empty cans (labels removed) or small ovenproof bowls upside down on a baking sheet. Drape a square of foil over each can and coat with cooking spray.
Fill a shallow bowl with 1/2 inch warm water; whisk in the olive oil. Soak each tortilla in the water until soft, about 5 seconds, then drape over the prepared cans, pleating as needed. Bake until golden, about 5 minutes. Remove from the oven and invert the tortilla bowls onto the baking sheet; remove the cans and foil. Spray the inside of the tortilla bowls with cooking spray, season with salt and continue baking until crisp, 4 to 5 more minutes; let cool.
Meanwhile, make the steak: Whisk the dried garlic, onion and oregano, the cumin, chile powder, scallions, Worcestershire sauce, olive oil, 1 1/2 teaspoons salt and 1 teaspoon pepper in a bowl. Put the steak in a shallow dish and rub with 2 tablespoons of the spice mixture (reserve the rest for the dressing). Add the bell pepper and sliced onion and toss. Cover and refrigerate 30 minutes or up to 4 hours.
Heat a large cast-iron skillet over high heat. Add the steak and scatter the bell pepper and onion around it. Sear the steak about 5 minutes per side, then transfer to a cutting board. Continue cooking the pepper and onion until just tender, about 3 more minutes. Thinly slice the steak against the grain, then cut into 1-inch pieces.
Assemble the salad: Whisk the mayonnaise, buttermilk and the reserved spice mixture in a large bowl until smooth. Add the cucumber, lettuce, beans and olives and toss. Divide the salad among the tortilla bowls. Top with the steak, bell pepper, onion, cheese and salsa.
Photograph by Kang Kim
Recipe courtesy Food Network Magazine