Mix together all ingredients for marinade. Add steak and marinade steaks in this mixture for 30 to 45 minutes. Grease grill with oil and heat until hot. Drain steaks and grill 5 to 7 minutes per side or for desired doneness. Let rest, then slice against grain. Warm tortillas on periphery of grill. Cut avocadoes in half and remove pit, but don't peel. Brush avocado with oil and place cut side down until grill marks appear. Scoop out avocado flesh and divide over tortillas. Divide steak slices over tortillas and wrap into a cone. Eat warm.