In this hot climate, drying is a common way of preserving food. We came upon these ladies making small tortilla-like cakes. First they made a firm dough, then broke pieces off and roll them between their hands into small balls. These were flattened, and sandwiched between sheets of plastic wrap. Finally, they were set out on bamboo racks to dry by the roadside. They look like speckled popadoms and I think they are made with some kind of yam.
River weed is another local specialty. You can buy it at the market in thin dark green sheets speckled with sesame seeds. It's served deep-fried, and often smeared with chili paste. One afternoon, I was exploring the banks of the Mekong and found this lady using a plastic bag to harvest weed from the river.
Finally, rice cakes drying in the sun. I'm guessing they're eaten as snacks.