In a large mixing bowl, combine the shredded cabbage and chopped cilantro.
In a small separate bowl, whisk together the lime juice, vegetable oil, and salt. Do not pour the dressing over the cabbage until about 10 minutes before you are ready to eat.
Set the bowl in the refrigerator to keep the vegetable cell walls rigid.
In a food processor or using a sturdy whisk and a bowl, mash the avocado until smooth.
Incorporate the sour cream, lime juice, garlic powder, and salt. Whisk vigorously until the mixture is aerated and light.
If the mixture is too thick, add one teaspoon of water at a time until it reaches a "drizzlable" consistency.
Cover and refrigerate immediately.
Take your peeled and deveined shrimp and place them on a layer of paper towels.
Pat them dry thoroughly on both sides.
Once dry, place the shrimp in a bowl and toss with the garlic powder, onion powder, cumin, smoked paprika, salt, pepper, and one tablespoon of the vegetable oil. Ensure each shrimp is evenly coated in the spice rub.
Place a large skillet or cast-iron pan over medium-high heat.
Add the remaining tablespoon of vegetable oil.
Once the oil is shimmering (but not smoking), add the shrimp in a single layer.
Cook the shrimp for 90 seconds on the first side without moving them. You will see the edges turn pink and opaque. Flip the shrimp and cook for another 60 to 90 seconds. Use a digital thermometer to ensure the thickest part of the shrimp has reached 145°F.
Once they form a "C" shape, remove them immediately from the pan to a clean plate.
Retrieve the slaw and the crema from the refrigerator.
Toss the cabbage with its dressing now. Lay out a warm tortilla.
Place a generous spoonful of the zesty slaw in the center.
Top with 3 or 4 seared shrimp.
Drizzle the avocado crema over the top.
