In a large bowl or zip-lock bag, whisk together the avocado oil, tamari, sesame oil, lime zest, cumin, garlic powder, chili powder, salt, and pepper. Add the steak and turn to coat evenly.

Marinate at room temperature for 20 minutes, or cover and refrigerate for up to 24 hours. If refrigerating, remove the steak from the fridge 20–30 minutes before grilling to take the chill off.

In a food processor, combine the jalapeño, green onions, cilantro, avocado oil, lime juice, red wine vinegar, salt, and pepper. Pulse until finely chopped but still slightly textured — you don't want it fully smooth. Taste and adjust seasoning as needed. Set aside.

Preheat your grill to high heat. Remove the steak from the marinade and let any excess drip off. Grill for 3–4 minutes per side for medium-rare, or until cooked to your desired doneness.

Transfer to a cutting board and let rest for 5 minutes, then slice thinly against the grain.

Warm the tortillas directly on the grill grates for about 30 seconds per side until soft and lightly charred.

Build the tortillas (street taco style) and layer with a few slices of steak, avocado, a spoonful of diced white onion, a pinch of fresh cilantro, and a generous drizzle of jalapeño chimichurri. Serve with lime wedges alongside.