Crispy roasted chickpeas (optional, see notes):
Drain and rinse chickpeas. Spread the chickpeas out on a towel-lined baking sheet, gently rub them to dry, and remove any peels. You can opt to peel all the chickpeas; they do tend to crisp up more, or leave them on. Remove towel and place the baking tray in the oven while it preheats, set oven to 350°F. This will dry them out helping them to crisp up fully. Once the oven heats up to temperature, about 20 minutes, remove tray from oven and drizzle chickpeas with olive oil and put tray back in the oven.
Roast the chickpeas for 45 minutes, rotating and stirring half way through baking. They should be dry, crispy, and lightly toasted. If not quite done, turn oven off and leave tray in until done. They crisp more while they cool.
Toss with seasonings while still warm. Store on the counter at room temperature, uncovered, for a day. If there are any left after this, seal in an airtight container. They are at their finest when freshly baked.
Tahini Sauce: Whisk together tahini paste, water, lemon juice, olive oil, garlic, salt and pepper in a small bowl. Adjust to taste, adding more water, lemon, or salt.
Assemble Chickpea Bowls: Divide quinoa and chickpeas among the bowls, and arrange cucumbers, tomatoes, bell pepper, onions, and olives. Sprinkle with fresh herbs and generously drizzle with tahini sauce.