Peel the hard boiled eggs, slice them in half, and scoop the yolks into a small mixing bowl. Set the egg white halves onto a platter.
Mash the egg yolks with a fork.
Add the mayonnaise, mustard, vinegar, salt and pepper to the bowl, and stir to combine until smooth. Optional - if you'd like the mixture to be more orange than yellow, add one drop of red food coloring and mix.
Add the egg yolk mixture to a piping bag with the piping tip of your choice.
Pipe the yolk filling into the egg white halves to form circles for the pumpkins.
Use a toothpick to lightly draw lines into the "pumpkins".
Slice a few chives into ¼-½ inch pieces.
Place the chive pieces onto your egg pumpkins as stems.
Sprinkle with paprika.
Chill in the refrigerator in an airtight container until ready to serve.
Notes
Store leftovers covered in the fridge for up to 4 days. If you'd like the yolks to be more vibrant, you can add some red or orange food coloring to the mixture.