Position racks in the upper and lower thirds of the oven; preheat to 350 degrees F. Line 2 baking sheets with parchment paper. Whisk the flour, baking powder and salt in a medium bowl. Beat the granulated sugar and eggs in a large bowl with a mixer on high speed until pale and very thick, about 5 minutes. Add the ricotta, olive oil, 1 teaspoon tangerine zest and the vanilla and almond extracts; beat until combined. Reduce the mixer speed to low; beat in the flour mixture until just combined. The dough will be loose - similar to a thick cake batter.
Drop tablespoonfuls of dough onto the prepared baking sheets, about 1 1/2 inches apart. Bake, switching the pans halfway through, until the cookies spring back when gently pressed, about 12 minutes. Let cool completely on the baking sheets.
Make the glaze: Whisk the confectioners' sugar, the remaining 1/2 teaspoon tangerine zest and 2 tablespoons hot water until smooth, adding up to 1 more tablespoon hot water if needed. Spoon about 1/2 teaspoon of the glaze over each cookie and spread with the back of the spoon. Decorate with nonpareils. Let set, 30 minutes.