In shallow glass dish, combine oil, lime juice, vinegar, onion, garlic, chili powder, salt and cumin.
With meat mallet, pound steak to 1/4-inch thickness.
Place steak in marinade; turn to coat.
Cover and refrigerate several hours or overnight, turning several times.
Drain steak; discard marinade.
Grill steak, on covered grill, over medium-hot Charcoal Briquets 4 to 8 minutes on each side, or until done.
Cut bread into 1- inch slices and toast on grill.
Carve steak into 3/4-inch diagonal strips.
Arrange steak on toasted bread.
Top with hot salsa and guacamole.