Preheat the oven to 350 degrees.

Whisk the flour, cocoa, baking soda, and salt together in a large mixing bowl. Combine the margarine, sugar, soy milk, vanilla and peppermint extract in a separate bowl. Add the wet ingredients to the dry ingredients to form a dough.

Pinch off pieces of dough and roll them into patties. Place them on a lightly greased baking sheet. Bake the cookies for 15 to 20 minutes, or until they look done. Allow them to cool completely on a wire rack.

In a small sauce pan over medium heat, combine the soy milk, margarine, and sugar. Bring to a boil, then lower the heat and simmer for five minutes. Remove from heat and add the chocolate chunks, stirring constantly until smooth.

Spread the frosting over the cooled cookies while it's still warm. Quickly sprinkle with crushed peppermints, then allow the frosting to set for at least ten minutes before serving.