Prep the shrimp: Pat the shrimp dry with paper towels.
Toss with 1/2 teaspoon salt, 1/4 teaspoon black pepper, smoked paprika, and cumin. Set aside for 5 minutes.
Make the quick slaw: In a bowl, mix Greek yogurt, mayonnaise, lime juice, and a pinch of salt. Add the shredded cabbage and toss to coat.
Taste and adjust with more lime or salt if needed. Chill while you cook.
Warm the tortillas: Heat a dry skillet over medium and warm tortillas for 30 seconds per side until pliable. Wrap in a clean towel to keep warm.
Cook the garlic butter: In a large skillet over medium heat, add olive oil and butter.
When the butter foams, add minced garlic and chili flakes. Stir for 30–45 seconds until fragrant, not browned.
Sauté the shrimp: Add the seasoned shrimp in a single layer. Cook 1.5–2 minutes per side until pink and opaque.
Do not overcook.
Finish with lemon and herbs: Turn off the heat. Add lemon zest, a squeeze of lemon juice, and chopped cilantro. Toss to coat.
Taste and adjust salt, pepper, and lemon.
Assemble the tacos: Layer slaw in warm tortillas. Add a generous spoonful of shrimp and some of the garlicky butter from the pan. Top with avocado, pickled onion, and cotija if using.
Serve with lime wedges and hot sauce.