Wash the red beans thoroughly.
Put the red beans in a pot, add water, and bring to a boil.
When it starts boiling, discard the first water, add fresh water, and simmer the beans until they are soft.
Drain the cooked beans through a sieve.
Mash the beans finely or blend them in a mixer.
In a pan, add the mashed beans, sugar, and salt. Stir over medium heat until thickened.
When the moisture evaporates and it becomes a paste, remove from heat and let it cool.