Rinse and pat the shrimp dry. Mix together shrimp, ½ tablespoon olive oil, chili powder, garlic powder, cumin, and salt. Let sit.
In a blender or food processor, blend together the yogurt, ½ tablespoon olive oil, garlic clove, jalapeño, avocado, salt, and zest and juice from the lime.
Place the cabbage in a bowl and toss with ½ cup sauce. Reserve the rest of the sauce for serving.
In a large nonstick skillet, heat the remaining ½ teaspoon olive oil over medium-high heat. Add the shrimp and saute until the shrimp is cooked through, about 4 minutes. Transfer to a plate.
Warm the tortillas and assemble the tacos. Fill the tortillas with shrimp. Top with cabbage mixture, extra cabbage, and a squeeze of lime juice.
Note: For shrimp tacos using frozen shrimp, you can thaw the shrimp in your refrigerator overnight, or if you forget, you can quickly thaw them too. Place the shrimp in a mesh colander then submerge the colander in cool water for 15-ish minutes. Do not use hot water.