Pat the shrimp dry. In a medium bowl, mix the shrimp with the garlic, cumin, cayenne, and salt.
In a large skillet, heat the butter or olive oil on medium high heat. Cook the shrimp for 1 to 2 minutes per side until opaque and cooked through, turning them with tongs.
Spritz with lime juice and stir in the lime zest and chopped cilantro. Serve immediately.