For the dough:
Heat water and butter in a medium saucepan over medium heat until butter has melted. Let cool slightly. Mix flour, salt, and paprika in a large mixing bowl and make a well in the center. Pour melted butter mixture into flour mixture and mix with your hands until you get a wet, oily dough. Shape dough into a disk and wrap in plastic. Refrigerate for at least 2 hours or overnight.
For the filling:
Heat a large skillet over medium-high heat and add chorizo, breaking apart into small pieces, then add onion. Saute until chorizo is cooked through. Turn off heat, add diced and boiled potatoes, and let cool completely.
While the filling is cooling, preheat oven to 400 degrees F. Spray a large baking sheet with non-stick spray or line with parchment. Tear off pieces of dough to roll about 20 golf-sized balls. Using a rolling pin, roll out dough balls on a lightly floured surface into 5″ circles. Place 2-3 tablespoons of cooled filling into the center of each dough circle. Fold dough over filling to make a half-moon shape and press edges firmly to seal. Crimp with the back of a fork. Place empanadas on baking sheet and bake until golden brown, 15-20 minutes. Let cool.
For avocado cream:
While the empanadas cool, place sour cream, half and half, lemon juice, and jalapeno in the bowl of a blender or food processor. Blend until smooth. Peel, pit, and dice the avocado and add to blender. Blend until smooth and creamy. Season with salt. If not serving immediately, wrap tightly with plastic wrap, pressing plastic onto the surface of avocado cream to prevent browning.