In a medium bowl, beat the palm oil with a hand held blender until creamy
Blend in the powdered sugar, salt, vanilla, and rice milk, and cream together until well blended
Adjust the consistency of the frosting by adding more rice milk to thin it or adding more powdered sugar to make it thicker.
For chocolate buttercream frosting, replace 1/4 cup of the powdered sugar with 1/4-1/2 cup cocoa powder, depending on how dark you want the chocolate flavor
*If you don't want to use palm oil, you can use completely softened dairy free butter and omit imitation butter flavor. You may need to add a bit more powdered sugar to get the stiffness/structure in the frosting that you prefer.