In a medium bowl whisk together the all-purpose and whole-wheat flours, baking powder and salt. In a large bowl beat together the sugar, eggs, oil, orange zest and vanilla extract until well combined. In batches, add the dry ingredients until the mixture forms a dough. Stir in the cherries, almonds and chocolate.
Transfer the dough to a floured work surface and knead several times. Shape into a log about 10 inches long and 3 inches wide. Transfer to a parchment-lined baking sheet and bake for 25 minutes. Transfer to a wire rack and let cool for 15 minutes. With a serrated knife, cut 1/2-inch diagonal slices. Arrange on the baking sheet, cut-side down, and bake 10 minutes. Turn the biscotti over and bake until golden, 5 to 10 more minutes. Transfer to a wire rack to cool.