Whisk together spelt flour, sugar, cocoa, baking powder, and salt in a large bowl. Make a well in the center. In a medium bowl, lightly beat the eggs with a fork. Gradually drizzle in the olive oil until well blended, followed by the liqueur, zest, and vanilla. Pour the egg mixture into the center of the flour mixture. Using a dough whisk or a wooden spoon, and stirring from the center, combine the ingredients until much of the flour is incorporated. Briefly stir in the melted chocolate. Add the figs and, using your hands, gently bring the dough together into a soft ball. Cover the bowl with a plate and set aside for 20 to 30 minutes. This allows the bran to soften for a more appealing texture.
Meanwhile, place a rack in the center of the oven and preheat to 350ºF. Line a large rimless baking sheet with parchment paper. Lightly grease your work surface with olive oil.
Cut the dough inside the bowl into 4 equal pieces. Lightly knead each piece and gently roll into a log, about 9 inches long, pressing in any protruding pieces and moistening your hands with oil if needed. Try to make the log as smooth as possible. If the dough cracks, gently push it together. Place the logs crosswise on the prepared baking sheet, leaving at least 2 inches in between. Gently pat down the top of each log until it is about 1 1/2 inches wide.
Bake until the logs firm up and small cracks appear on top, about 25 minutes. Remove the baking sheet from the oven, and carefully slide the parchment paper with the logs onto a wire rack. Allow to cool completely, about 60 minutes (or up to 1 day).
Reduce oven temperature to 300ºF. Transfer the logs to a cutting board (loosen with a metal spatula if needed). Using a large serrated knife, gently cut each log diagonally into 3/4-inch thick slices. Place the slices, cut side down, onto the baking sheet without touching.
Bake until the biscotti feel dry to the touch but still yield a bit, about 25 minutes. Carefully transfer the biscotti to a wire rack to cool completely before storing; they will crisp as they dry.