Prepare a large baking sheet by lining it with parchment paper.
In a food processor, blend the Oreo cookies into fine crumbs. Alternatively, place them in a plastic bag and crush them with a rolling pin until they form a crumbly texture.
In a large bowl, use an electric hand mixer to blend the softened cream cheese until smooth. Add the Oreo crumbs to the cream cheese, mixing until well combined.
Using a 1.5-inch cookie scoop, portion the mixture and roll each portion into a smooth ball between your hands. Place each ball on the prepared baking sheet. Refrigerate for at least 2 hours to help the balls hold their shape before dipping.
Set aside ½ cup of the candy melts if you'd like to add a decorative drizzle later.
In a double boiler over low heat, melt the remaining green candy melts, stirring regularly until smooth. Avoid overheating or introducing water into the candy, as it can cause it to seize.
Dip each chilled ball into the melted candy using a fork or toothpick. Gently tap the fork on the edge of the bowl to remove any excess candy, then place each coated ball back on the parchment-lined baking sheet.
If adding a drizzle, melt the reserved ½ cup of candy melts in a microwave-safe piping bag. Microwave on a low setting (such as the defrost setting) for 30-second intervals, kneading the bag between each interval until fully melted. Cut a small tip off the piping bag and drizzle over the coated balls.
While the drizzle is still wet, top each Oreo ball with a red candy heart. Return the balls to the refrigerator until the candy coating has completely set.