I am not sure what language thokku is in, most likely Telugu, but it refers to any fresh herb/vegetable pounded/ground to a paste with salt, tamarind and jaggery, and reduced in sesame oil. The key ingredients are tamarind, jaggery, and sesame oil. This recipe makes a thokku out of fresh green chilies and is dynamite!
This recipe is from our friend Gautam, who dabbles in gardening, cooking, baking, grilling, photography, and on the side, is a neurosurgeon! He grows a bunch of varieties of green chilies including some of the hottest varieties, and like any Indian worth his salt, pickles them. I love this pickle and followed his recipe to make my own from my garden produce, as I was running out of his stock! Eyeballed most of the ingredients.