Place chick peas in a bowl, cover with water by at least 2 inches, and soak overnight.
Meanwhile, wash the chard, cut off the thick stems and finely chop them. Add chopped stems to saucepan and simmer for 5 minutes. Finely chop the leaves, add them to the saucepan, and simmer an additional 25 minutes. Add the lemon juice, salt, pepper, pureed garlic and mint, stir well and simmer 5 minutes. Remove soup from the heat, and adjust the seasonings. If soup is too thick, add more boiling water.