Combine the sugar, salt, and 1/2 cup water in a 2-quart saucepan over medium heat. Bring to a boil and make sure the sugar has dissolved; add the chiles. Reduce the heat to medium-low and simmer for 2 minutes. Remove from the heat and let the syrup cool completely. Strain through a fine strainer into a 1-quart liquid measuring cup, and discard the solids in the strainer.
Puree the pineapple in batches in a blender. Measure out 2 cups of puree (save any extra for another use) and combine it with the syrup.
Distribute the coconut among ten 1/3-cup pop molds. Add the fruit mixture to each mold, leaving about 1/4 inch at the top to allow for expansion. Stir gently with a Popsicle stick to distribute the coconut. Freeze until partially frozen, about 1 hour. Insert sticks and freeze again until the pops are fully set, 4 to 6 hours more.
To unmold, dip the mold in a deep pan of hot water until the pops pull out easily, 30 to 40 seconds, or let sit at room temperature for 5 to 10 minutes. Unmold and store the pops in individual resealable plastic bags; they’re best eaten within 3 weeks.