Pat the shrimp dry. Moisture is the enemy of a good sear. Use paper towels to dry the shrimp well.

Mix the marinade. In a bowl, whisk together 2 tablespoons oil, the zest of 1 lime, the juice of 1.5 limes, garlic, chili powder, smoked paprika, cayenne, cumin, salt, and black pepper.

Toss and rest briefly. Add the shrimp to the bowl and toss to coat. Let it sit for 10–15 minutes at room temperature. Don’t go much longer or the acid can make the shrimp rubbery.

Heat the pan. Place a large skillet over medium-high heat and add a thin slick of oil. You want the pan hot before the shrimp go in.

Cook in batches. Arrange shrimp in a single layer. Cook for 1.5–2 minutes per side, until pink and just opaque with light char marks. Avoid overcrowding; do 2 batches if needed.

Finish with lime. Remove from heat and squeeze the remaining half lime over the shrimp. Taste and adjust salt if needed.

Garnish and serve. Sprinkle with chopped cilantro. Serve over cauliflower rice, in lettuce cups, or on a salad with avocado.