Cook Zucchini. In a non-stick pan or skillet, heat 2tbsp olive oil over medium-high heat until shimmering but not smoking. Add the sliced zucchini and saute on both sides until tender. Remove zucchini with a slotted spoon and place on a paper towel to drain any excess oil. Season lightly with salt.
Prepare dressing. Add the dressing ingredients to a mason jar. Close the lid tightly, and give it a good shake. Set aside for now (but shake again before using).
Assemble grain bowls. Divide the cooked farro, lentils, and chickpeas equally among four dinner bowls (it’ll come to 1/2 cup of each per bowl). Add cooked zucchini, tomatoes, shallots, avocado slices, parsley, and kalamata olives. Season lightly with salt, pepper and more za’atar, if you like. Drizzle a bit of the dressing on top (about 2 tbsp per bowl). Finish with crumbled feta, if you like.
Serve at room temperature or warm, if farro and pulses were just cooked. It’s best to mix the ingredients in each bowl to allow the dressing flavors to infuse. If you have a bit of dressing left, serve it alongside.