Add all of the ingredients for the sweet chili sauce into a small saucepan over medium heat. Whisk the ingredients together until they are warm and remove from heat. Allow the sauce to cool and thicken.
Once cooled, place the shrimp into a zip-top plastic bag, and cover them with ¼ cup of the sweet Thai chili sauce. Set the rest aside in the saucepan. Remove as much air as possible from the bag before sealing. Massage the shrimp to ensure they are all covered with sauce, then place in the refrigerator for two to four hours.
(Grill) Light your grill and set it up for medium high direct heat. While the grill is preheating, place the shrimp on the skewers and discard any sauce that touched the raw shrimp. OR
(Stovetop) Preheat a heavy bottom skillet with sesame oil over high heat. When the oil starts to shimmer, add the shrimp and spread out evenly in the pan, reduce the heat to medium high. Flip after two minutes, add the optional sliced jalapeno and sear for an additional two minutes till charred and cooked through. Proceed to step six.
Once the grill is preheated, place the shrimp and the reserved sauce (in the saucepan) on the grill directly over heat. Cook the shrimp till they reach desired doneness and have a nice char, flipping them after two minutes. (about 4-5 minutes total) Occasionally stir the sauce to warm it through.
Remove the shrimp from the grill and glaze them with the warm chili sauce. Finish with cilantro and toasted coconut. Whisk the remaining toasted coconut into the creamy Thai sauce and serve alongside the shrimp.