Combine avocado, onion, tarragon, cayenne and vinegar in a medium bowl. Season with salt and pepper. Gently stir salsa to combine.
Preheat a chargrill pan or plate over high heat. Lightly brush both sides of each steak with oil. Cook steaks on 1 side until the first sign of moisture appears on the surface. Turn and cook for 1-2 minutes or until cooked to your liking (see tip). Transfer to a plate. Loosely cover with foil and set aside to rest for 5 minutes to allow the meat fibres to relax and reabsorb their juices.
Serve steaks with avocado salsa.
For rare or medium, only turn steak once (steak should still feel soft when pressed with your tongs). For well done, turn steak again when moisture reappears on the surface, then reduce heat until cooked through (steak should feel firm when pressed with your tongs).
Serving Size 2