Dry-brine the shrimp. Toss the shrimp with 1 tsp kosher salt in a bowl and let them sit for 10 minutes. This isn’t just seasoning the salt draws surface moisture out of the shrimp, and that moisture is exactly what stops them from browning in the pan. Skipping this step is the single most common reason shrimp tacos turn out pale and steamed instead of crispy.
Pat them completely dry. After 10 minutes, spread the shrimp on paper towels and pat them until they’re genuinely dry not just blotted. Any surface water left behind will hit the hot pan and turn straight to steam, which drops the pan’s temperature and stalls the sear before it starts.
Season. In the same bowl, toss the dried shrimp with olive oil, chili powder, cumin, smoked paprika, garlic powder, and black pepper until evenly coated.
Make the slaw. While the shrimp season, combine the cabbage, cilantro, mayo or crema, lime juice, and a pinch of salt in a separate bowl. Toss well and set aside the slaw actually improves as it sits for a few minutes, since the lime softens the cabbage slightly.
Sear the shrimp: Heat a skillet over medium-high until it’s genuinely hot a drop of water should sizzle immediately on contact. Add the shrimp in a single layer, without crowding the pan, and let them cook undisturbed for about 90 seconds per side, until the edges are golden-orange and slightly charred and the shrimp are opaque all the way through (internal temp around 120°F/49°C is fully cooked). Pro tip: resist the urge to stir them constantly moving shrimp around too much is what keeps them from ever developing a sear in the first place.
Finish with lime. Off the heat, squeeze the juice of half a lime directly over the hot shrimp and toss briefly. The acid brightens the spices without cooking off, since the pan is no longer actively heating.
Warm the tortillas. In a dry skillet over medium heat, warm each tortilla for 20–30 seconds per side until pliable and lightly speckled.
Assemble. Layer a scoop of slaw onto each tortilla, top with 3–4 shrimp, a few avocado slices, and a sprinkle of cotija. Serve immediately with extra lime wedges.