Step 1

Zest and juice 2 of the limes (you should have about 1 tablespoon zest and 1/4 cup juice) and add to a medium glass bowl. Peel and grate the ginger and garlic and add to the bowl along with the red pepper flakes, canola oil, coconut milk and 1 1/2 teaspoons salt. Stir to combine.

Step 2

Marinate in the refrigerator for 30 minutes. Meanwhile, cut the remaining lime into wedges. Reserve for serving.

Step 3

Heat a large grill pan over medium-high heat. Remove the shrimp from the marinade and put on a baking sheet lined with paper towels; don't worry if the coconut milk has hardened while it was in the refrigerator. In batches, cook the shrimp until lightly charred in spots on both sides and just cooked through, about 3 minutes total. Remove from the heat and transfer to a large plate.

Step 4

Top with the sliced scallion and serve with the reserved lime wedges.