Soak and peel the beans, blend the peeled beans with a small amount of water until smooth and thick, pour the blended paste into a whisking machine or whisk manually using a mortar and pestle to achieve a fluffy texture, transfer the mixture into a bowl and add salt to taste, heat vegetable oil in a frying pan over medium heat, dip each slice of bread into the bean paste ensuring both sides are evenly coated, gently place the coated bread into the hot oil, fry until both sides are golden brown and crispy, remove from the oil and place on paper towels to drain excess oil, serve hot and enjoy your delicious, protein-rich Tsumbuka!