Fill a medium saucepan ¼ full with water and bring to a boil.
Melt the chocolate by pouring the chocolate chips into a medium sized bowl, and then placing the bowl in the saucepan, making sure the bottom of the bowl does not touch the boiling water. Stir constantly until the chocolate chips are melted.
Remove from heat and set the bowl next to the workspace.
Dip half of a pretzel rod in the chocolate, then place it on the cookie sheet and immediately sprinkle with rock salt, to taste.
Place the pretzels in the refrigerator to harden the chocolate, 5–10 minutes.