Preheat the oven to 400 degrees. Line a sheet pan with parchment paper.
In a large bowl, whisk together the lime juice, orange juice, oil, garlic powder, ground cumin, oregano, salt and black pepper until combined. Add the sliced mushrooms and onions and toss until the mushrooms and onions are evenly coated.
Spread the mushrooms and onion mixture onto the prepared sheet pan in one layer.
Bake for about 20 to 30 minutes, stirring them halfway through.
Once the mushrooms are slightly crispy on the edges, but still juicy remove from the oven.
While the mushrooms are in the oven, make the sauce. Combine all ingredients in a blender until incorporated. Set aside.
Serve the mushrooms in warmed tortillas of your choice with cilantro, crumbled cotija cheese, fresh lime wedges and cilantro lime cream sauce.