01 - Combine the cubed watermelon, lime juice, and agave syrup if desired in a blender. Purée until completely smooth.
02 - Pour the watermelon purée evenly into popsicle molds, filling each roughly two-thirds full. Gently tap the molds on the counter to release any trapped air bubbles.
03 - Place the molds in the freezer for about 1 hour, or until the watermelon layer is slightly firm to the touch.
04 - While the watermelon layer sets, blend the peeled kiwi slices, lime juice, and agave syrup until smooth.
05 - Once the watermelon layer has firmed up, pour the kiwi purée on top in each mold, filling nearly to the rim. Insert popsicle sticks into the center of each mold.
06 - Return the molds to the freezer and freeze for a minimum of 3 hours, or until the pops are completely frozen through.
07 - Run the outside of each mold under warm water for a few seconds, then gently pull the pop free from the mold.