Preheat the oven to 350 F. In a medium bowl, whisk together flour, salt and baking soda. In a large bowl, mix together butter, peanut butter, and both sugars until fluffy. Add in the egg and vanilla extract until smooth.
Add in the flour mixture and mix until it is fully combined. In a shallow dish, combine granulated sugar and ground cinnamon. Roll the cookie dough into balls and roll in the cinnamon sugar mixture. Place cookies onto a large ungreased baking sheet at least 2-inches apart.
Bake for 10-12 minutes. Remove from the oven and decorate with icing and candy eyes.