Put water into a small pot and bring to a boil. Remove from the heat, add dates, cover and set aside to let steep for 5 minutes; drain well. Transfer dates to a food processor, add cashews, soymilk and vanilla and pulse, scraping down the sides of the bowl often, until smooth.

Transfer date mixture to a large bowl, stir in 1/2 cup cocoa, sugar, cinnamon and salt. Transfer remaining 1/2 cup cocoa to a wide, shallow dish. Make each button by forming about 1 teaspoon of the cocoa mixture into a ball. Roll in cocoa, and then press flat with your thumb; transfer to a large parchment paper-lined sheet tray as done. Set aside to let firm up a bit, 3 to 4 hours.