Thaw the salmon fillets overnight in the refrigerator or under gently running water.
Preheat your grill to medium or roughly 375-400 degrees.
Melt the butter and add the garlic and honey. Stir.
Zest the rind of one lime into the butter, set lime aside. Add the chopped cilantro, along with salt and pepper to taste. Quarter the zested lime and squeeze the juices into the bowl. Mix well.
Swirl a spoon of the mixture onto the center of a foil piece. Arrange a layer of the sliced summer squash, then place salmon over the vegetables. Next scoop the cilantro sauce onto the salmon.
Fold the sides of the foil in and pinch to seal.
Grill for about 15 minutes. Times will vary, based on actual temperature of grill and thickness of the salmon fillets. I check mine shortly before 15 minutes and reseal if more cooking is required.
Notes
*nutrition based on ¼ teaspoon sea salt used to make topping