Roast sesame seeds and peanuts separately. Cool and make a powder. I always keep roasted sesame and peanuts handy in my pantry as I use these two ingredients a lot in my cooking.
In a spice grinder, grind dry red chilies and fenugreek seeds to powder. This step is optional. Skip this step if using an Indian mixie.. These ingredients do not grind well in US blenders and food processors. Hence I do this additional step.
Heat oil in a pan. Add curry leaves, green chilies, cumin and saute until chilies change color. If using whole dry red chilies (skipped above step), add in this step.
Add garlic, spices powder (red chilies and fenugreek powder), salt, turmeric and stir.
Add zucchini pieces, stir until spices coat the veggies and are lightly roasted.
Add tamarind and give it a good stir. If using tamarind paste or concentrate, add after the zucchini is cooked.
Cover and cook until the zucchini is tender. Zucchini cooks very fast and keep an eye on it.
Remove cover and continue cooking until the mixture is dry. If using tamarind paste or concentrate, add at this step.
Add sesame powder and peanut powder and salt. Stir and turn off the heat.
Let the mixture cool completely and grind to a coarse paste. If necessary add some water. I ground in a food processor as I wanted a coarse texture and did not add any water.
Transfer to a bowl, taste the pachadi and adjust salt. If the chutney is not tangy enough to your taste, add homemade tamarind paste/concentrate to taste. Or add a few drops of lime juice.
Serve chutney with rice, dosa or use as a spread for sandwiches.