In small bowl, stir together plain yogurt and cilantro. Cover and refrigerate until ready to use.
In a medium size bowl, mix shrimp, chili powder, cumin, and garlic. In large skillet, heat oil over medium heat. Add shrimp to pan. Cook for 2 to 4 minutes ONLY until shrimp are pink. Cooking longer will make shrimp too tough and chewy. Remove from heat.
Meanwhile, warm corn tortillas.
Arrange shrimp down the center of the corn tortilla. Add shredded lettuce or cabbage, tomatoes, and 1 Tb of cilantro mixture. Serve and enjoy!