In a large soup pot, cook the onion, salt and garlic in the oil over medium heat, until it starts to color. Add the paprika, seasonings and chard stems, and stir fry for a minute. Add the rest of the vegetables, broth, and lemon juice/vinegar. Bring to a simmer, adding water to thin out the stew, if desired. Turn off the heat, ladle the stew into bowls, and enjoy.