Spicy Beef Stir-fry

Ingredients:
1 pound beef flank steak
2 tablespoons vegetable oil
1 teaspoon each ground cumin, garlic salt and dried oregano leaves
1 red bell pepper, cut into thin strips
1 medium onion, cut into thin wedges
1 to 2 jalapeno peppers, seeded and cut into slivers

Directions:
Cut beef lank steak diagonally across the grain into 1/8-inch slices. Combine oil, cumin, garlic salt and oregano. Heat 1 tablespoon of the oil mixture in wok. Add red pepper, onion, and jalapeno pepper; stir-fry 2 to 3 minutes or until tender-crisp. Remove from wok; reserve. Add remaining oil mixture and half of beef strips to wok; stir-fry 1 to 2 minutes or until no longer pink. Remove; keep warm. Repeat with remaining beef. Return all beef and tostada shells and top with Guacamole.