Use a food processor to grate the zucchini or you can do this by hand using a grater.

Melt coconut oil in a dutch oven (or heavy-bottomed pot) over medium heat. Add the mustard seeds and when they begin to splutter and pop, add the onion, Serrano pepper, and curry leaves. Stir-fry for 6-7 minutes or until the onions become fragrant and translucent.

Add the grated coconut, salt, turmeric, cayenne and stir, then increase the heat to medium-high and add the zucchini. Stir-fry for 5-6 minutes, or until the zucchini is cooked through.

If you'd like a "dry" thoran, use a slotted spoon to move the zucchini into a serving dish, leaving any liquid at the bottom of the pot (the liquid is really flavorful though, so don't toss it out - I slurp it up!).