Mix the sugar and orange zest on a small plate.
Run the lime or orange wedge along the rim of the glass.
Dip the edge of the glass into the sugar and orange zest mixture all the way around.
Add a bunch of ice to a martini shaker.
Pour in the two vodkas and orange juice and give it a good shake!
Pour into a martini glass and then top it off with soda.
Stir and serve.