Start by zesting the lime and then mixing the zest with 1 cup of plain Greek yogurt in a bowl. Add 2 minced garlic cloves, 1 tablespoon of finely chopped scallion, ½ teaspoon salt, and ½ teaspoon ground pepper. Stir until well combined, then cover and refrigerate for at least 10 minutes to let the flavors meld together.

Using a box grater, grate the medium-sized English cucumber, allowing the fresh juices to flow. Once grated, use a clean kitchen towel to squeeze out any excess moisture thoroughly. Fold the cucumber into the yogurt mixture.

In a mixing bowl, combine 2 tablespoons of olive oil, 2 minced garlic cloves, ½ teaspoon salt, ½ teaspoon ground pepper, and the juice from 1 whole lime. Stir to create a flavorful marinade. Add the shrimp, tossing until evenly coated. Let it marinate for about 10 minutes.

Heat a large skillet over medium-high heat. Add the marinated shrimp in a single layer. Cook for about 3-5 minutes, or until the shrimp turn pink and begin curling. Flip and cook for an additional 2-3 minutes until fully cooked through.

Once cooked, remove the shrimp from the skillet and place them in a serving dish. Squeeze the remaining lime juice over the warm shrimp and stir gently.

Serve the grilled shrimp alongside the chilled Tzatziki sauce for dipping.