Street stands in Mexico sell fresh fruit sprinkled with lime, chile, and salt. These pops capture that same zing. You can use any mold you like for these popsicles, but you'll get a different number of pops depending on the mold size.
3/4 cup (one 6-oz. can) pineapple juice
1/3 cup lime juice
Pinch of kosher salt
3 tablespoons sugar
1/4 teaspoon red chile flakes
1 1/3 cups very thin slices fresh pineapple, cut from narrow wedges (about 1/6 cored pineapple)
How to Make It
In a small bowl, whisk together pineapple juice, 3/4 cup water, the lime juice, salt, and sugar until sugar dissolves. Stir in chile flakes. Pour seasoned juice into a spouted measuring cup, then into 8 (1/4 cup) popsicle molds* to fill each by two-thirds (before each pour, stir liquid to distribute chile flakes). Add enough pineapple to each so liquid rises to the fill line.
Freeze pops until slushy (don't insert sticks yet), about 2 hours. With a chopstick, stir up fruit and chile flakes to distribute evenly. Insert sticks and freeze pops until solid, at least 4 hours more.
To remove popsicles from molds, either let sit at room temperature 5 minutes or run under warm water 10 to 15 seconds.
*We used 1/4-cup cylindrical molds from Aymuna ($99/8 molds; amazon.com).