How to Make It
Pat shrimp dry. Combine chile powder, black pepper, cayenne, and 1/4 teaspoon of the salt in a small bowl; sprinkle evenly over shrimp. Heat 1 tablespoon of the oil in a large skillet over high. Add shrimp; cook, stirring often, until opaque, 3 to 4 minutes. Transfer shrimp to a plate.
Add remaining 1/2 tablespoon oil to skillet; reduce heat to medium. Add pineapple and onion; cook, stirring occasionally, until pineapple is lightly caramelized, 5 to 6 minutes. Stir in shrimp; sprinkle with 1/4 teaspoon of the salt.
While pineapple mixture cooks, stir together yogurt, lime juice, and remaining 1/4 teaspoon salt in a small bowl. Divide pineapple mixture among tortillas; top with cabbage, and drizzle each with about 1 tablespoon of the yogurt sauce. Sprinkle with cilantro, and serve with lime wedges.