Marinate the Steak:
In a bowl, whisk together orange juice, garlic, olive oil, lemon juice, soy sauce, parsley, cilantro, and green onions.
Place the steak in a resealable bag or shallow dish and pour the marinade over it. Ensure the steak is well-coated.
Marinate in the refrigerator for a minimum of 4 hours or overnight for best flavor.
Prepare the Steak for Smoking:
Remove the steak from the refrigerator and pat it dry with paper towels.
Season the steak with your favorite rub or the homemade all-purpose rub (combine all rub ingredients).
Let the steak rest at room temperature for 20–30 minutes to allow the flavors to deepen and the meat to come up to room temperature.
Prepare the Chimichurri Sauce:
In a bowl, combine parsley, cilantro, green onions, garlic, oregano, red wine vinegar, olive oil, chili flakes (if using), salt, and pepper.
Stir well and refrigerate for at least 30 minutes to allow the flavors to meld.
Smoke the Steak:
Preheat your smoker to 300°F (149°C).
Place the steak on the smoker and cook until it reaches your desired internal temperature, flipping halfway through for even cooking.
For medium-rare, remove the steak when it reaches 125°F (52°C). Adjust for your preferred doneness.
Rest the Steak
Remove the steak from the smoker and loosely tent it with aluminum foil. Let it rest for 10–15 minutes to allow the juices to redistribute.
Assemble the Sandwich:
Slice the steak thinly against the grain.
Place the slices on your favorite bun and generously top with the chimichurri sauce.
Serve and Enjoy
Serve immediately and savor your smoky, flavorful steak sandwich!