Preheat oven 350 degrees F (180 C). Place rice cakes on rack and toast in the oven for 5 minutes to crisp up. Let cool completely.
Melt chocolate chips in microwave-safe bowl for 1 minute. Stir. Microwave at 15 second intervals until chocolate chips are completely melted, stirring after each 15 seconds.
Spread melted chocolate onto rice cake evenly with back of spoon. Place on rack.
If desired, top rice cakes with chopped nuts, fruits, seeds, etc., pressing gently into chocolate.
Move to the refrigerator for the chocolate to harden completely.
Store rice cakes in an airtight container in the fridge.