Rinse the quinoa thoroughly under cold water until the water runs clear, which removes any bitter coating. In a medium saucepan, bring the broth to a boil, then add the rinsed quinoa and ground cumin. Reduce heat to low, cover, and simmer for 15 minutes until the liquid is absorbed and the quinoa is tender. Remove from heat and let it sit covered for 5 minutes to finish cooking and cool slightly.
While the quinoa cooks, quarter the cherry tomatoes and finely dice the red onion. In a small bowl, combine the tomatoes and onion with the juice of 1 lime and toss gently to marinate. Chop the cilantro and set aside. I find that letting the tomato-onion mixture sit while the quinoa finishes cooking allows the flavors to meld and the lime to lightly pickle the vegetables.
Cut the large avocado in half lengthwise and remove the pit. Scoop half of the avocado into a bowl and mash it with the juice of 1 lime until you reach your desired consistency—I like to leave it slightly chunky for texture. Dice the remaining avocado half into quarter-inch pieces and set aside.
Once the quinoa has cooled slightly, fold it into the mashed avocado base, stirring gently to combine while preserving some texture. Drain and rinse the chickpeas if needed, then fold them into the mixture along with the marinated tomato-onion mixture from Step 2. Add the reserved diced avocado and fresh cilantro, then taste and adjust with the remaining lime juice as needed. For the best flavor development, I prefer to add the diced avocado and fresh cilantro at the end rather than earlier, so they stay vibrant and don't get broken down by mixing.