Place the steak in the slow cooker and season with chili powder, paprika, 1/4 of the red onion (chopped), garlic, and salt/pepper to taste.
Cook for 2 hours on high or 4 hours on low.
While the meat is cooking, create the avocado lime dressing recipe and place in the refrigerator.
Once the carnitas steak is finished cooking, slice into thin strips.
Lightly brown the tortillas in a pan with the olive oil.
Top each tortilla with lettuce, carnitas steak, feta, cilantro, the remaining 1/4 chopped red onion, and avocado lime dressing.