Mash the garlic in the mortar, with the salt. Make into a paste. Add the lime juice (fresh only) and then the oregano, cumin and pepper. Mix together into a paste and coat the flank steak. You can let the steak sit a bit (but remember that the salt may draw out the moisture.... I actually brined the steak first).
Head the egg to 800 or so, and grill, 2 minutes a side, by two flips. IOW, grill 2 minutes, flip, grill 2 minutes, flip, for a total of about 8 minutes. Wrap steak in foil and allow to rest about a half hour.
NOTE: For the ancho pepper, I used two knife tips, but this is old ancho pepper. I could notice just a hint of a bite to it. Jan, of course, didn't notice anything. I could have tolerated more, but I'd be careful in case the pepper is fresh.
I sliced the steak and served over a Caesar salad.