In a bowl, combine the steak, orange juice, lime juice, ¼ cup chopped cilantro, paprika, salt, onion powder, black pepper, smoked paprika, ground cumin and oregano. Toss everything to coat, cover and refrigerate 1 to 6 hours.
When ready to cook, preheat your Traeger Grill to 500F (475F if using a ModiFire Grill Grate) or a heavy-bottomed skillet or griddle over medium-high heat. If using a Traeger, add the avocado oil to the steak and toss to coat. If using a skillet or griddle, add the avocado oil to the pan and heat until shimmering. Transfer the steaks and green onions onto the grill or skillet/griddle and cook, undisturbed, until grill marks form or deeply seared, around 4 minutes for the steak and 2 minutes for the onion. Flip and cook the other side until grill marks form or deeply seared and the thickest part of the steak registers 125F for a medium-rare centre, around 4 more minutes for the steak and 1 minute for the onion. Transfer the steak and green onions to a cutting board and let them rest at least 6 minutes before slicing the steak into small cubes, leaving the onions whole.
While the steaks rest, warm the tortillas on the grill or skillet/griddle for 10-15 seconds per side. Alternatively, place a heat-safe wire rack over a gas stovetop and warm the tortillas directly over the open flame, 10-15 seconds per side.
In a small bowl, combine the remaining ¼ cup chopped cilantro and diced white onion and toss to incorporate.
To assemble the tacos, spread a layer of diced steak on to each tortilla, top with some of the avocado salsa and garnish with the fresh cilantro and onion mixture. Serve with the charred green onions, extra avocado salsa on the side and lime wedges for squeezing.