Preheat a skillet over medium-high heat and add the olive oil.
In a small bowl, mix the chipotle chili powder, garlic powder, cumin, salt, and black pepper. Rub this spice mixture all over the salmon fillet.
Once the skillet is hot, add the seasoned salmon and sear for about 4-5 minutes on each side, or until cooked through and flaky. Remove from heat and let it rest for a few minutes.
While the salmon is resting, warm the corn tortillas in a separate skillet over low heat for about 30 seconds on each side, or until pliable.
Flake the salmon into bite-sized pieces and assemble the tacos by placing some salmon on each tortilla. Top with shredded red cabbage, avocado slices, and chopped cilantro.
Serve with lime wedges and a dollop of sour cream, if desired.