In a large bowl, toss together the shrimp, cumin, and salt until well coated.
In a large skillet, heat the oil over medium heat. Add the garlic and stir for 30 seconds.
Add the shrimp to the pan and arrange in a single flat layer. Cook the shrimp for 1 to 2 minutes undisturbed. Flip the shrimp, cook for 1 minute more, then add the lime zest, lime juice, red pepper flakes (if using), and cilantro. Stir for another minute, or until the shrimp is cooked through.
