Preheat the oven to 350 degrees and line a muffin tin with 4 paper liners.
In a medium bowl, whisk together the flour, sugar, baking powder, and salt.
In a separate bowl, mix the vegetable oil, orange juice, egg, orange zest, and vanilla extract until smooth.
Pour the wet mixture into the dry ingredients and stir until just combined.
Divide the batter evenly among the 4 liners and bake for 18 to 20 minutes, or until a toothpick comes out clean.
Let the cupcakes cool completely in the tin.
Place the vanilla frosting in a bowl and stir in the orange food coloring until evenly tinted.
Spread the orange frosting over each cooled cupcake.
Use the black decorating icing to draw jack-o'-lantern faces on top of the frosting.