Line a baking sheet with parchment or waxed paper. Use a spatula to stir together the cream cheese, blue cheese, and cranberries in a medium bowl. If needed, break up larger chunks of blue cheese so that the mixture is smooth.
Use your hands to roll the mixture into heaping teaspoon-size balls and place them on the baking sheet. Tip: Dampen your hands with water to keep the mixture from sticking to them. Cover the cheese balls with plastic wrap and chill them in the refrigerator for two hours (this step can be done one day ahead).
While the cheese balls are chilling, toast the pecans. Heat the oven to 350°. Spread the nuts on a baking sheet and bake until they're slightly browned and fragrant, about 8 minutes. Let them cool completely, then finely chop them. (A food chopper allows kids to complete this step.) Transfer the nuts to a sheet of parchment paper or a medium bowl.
Roll each ball in the pecans and insert a pretzel stick. Keep the balls chilled until ready to serve.