For the pot likker:
In a large pot, sauté onions until translucent, then add garlic and red pepper flakes.
Season with salt and cook for another two minutes.
Add smoked paprika and cook for an additional 2 minutes.
Add vinegar and water then bring to a boil. Reduce heat and simmer for at least 20 minutes.
For the greens:
While the potlikker simmers, prep the greens by stacking one bunch of greens at a time; roll the stack tightly into a cigar shape then cut the greens lengthwise ¾ of the way down (keeping the stems and base of the greens intact); then cut into ¼-inch wide pieces.
Wash the greens.
Add sliced greens to the pot and simmer until tender, about 45 minutes, stirring occasionally.
Add more liquid, if necessary.
Season to taste with salt and pepper.
Serve hot.