If the shrimp are frozen, thaw them first. Remove the shells and veins from the shrimp. Rinse and pat them dry with paper towels. Place them in a large resealable plastic bag and set aside.

In a medium bowl, mix together the coconut milk, pineapple juice, 1/2 cup of cilantro, sweet chili sauce, lime zest, lime juice, and Sriracha. Pour half of this mixture over the shrimp in the bag and save the rest for later. Seal the bag and refrigerate for 30 minutes. After marinating, discard the marinade and drain the shrimp.

Thread the shrimp and pineapple chunks onto four 10-inch metal skewers. Brush the reserved mixture onto the skewers lightly.

Heat the olive oil in a large nonstick grill pan over medium heat. Place the skewers in the pan and cook for 5 to 6 minutes, turning once, until the shrimp are opaque and the pineapple starts to char. Brush occasionally with the reserved sauce. Sprinkle with crushed red pepper and garnish with extra cilantro and coconut flakes if desired.