01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the all-purpose flour, sticky rice flour, baking powder, baking soda, and salt until evenly distributed.
03 - In a large bowl, whisk the melted coconut oil and sugar until creamy and well combined. Stir in coconut milk, vanilla extract, and lime zest if using.
04 - Fold in the dry ingredients until just combined. Gently fold in the diced mango, being careful not to overmix.
05 - Scoop tablespoonfuls of dough and roll into balls. Roll each ball in the granulated sugar for even coating.
06 - Place the dough balls on prepared baking sheets, spacing 2 inches apart. Gently flatten each ball with your palm or the bottom of a glass.
07 - Bake for 11 to 13 minutes, until edges are set and bottoms are just golden brown. Centers will remain soft.
08 - Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely before serving.