Put the tamarind in a bowl, add 2 tablespoons of water and soak for 10 minutes. Using your hands, mix well then squeeze out the pulp through a sieve (strainer). Set the extract aside and discard the pulp.
Heat the oil for the tempering in a large, heavy-based frying pan (skillet) over medium heat, add all the ingredients for the tempering, and stir-fry for about 1 minute, or until the mustard seeds start to splutter.
Add the okra, turmeric, and tamarind extract, then cover and cook for about 5 minutes, or until the okra are tender and all the moisture has evaporated.
Add the ground sesame seeds and season with salt, then stir-fry over high heat for a further 2 minutes, or until everything is well mixed and dry.