Preheat oven to 400°F
In a stockpot over medium-high heat, warm the oil.
Add garlic, onions, and all the spices. Sauté until the onions are tender and fragrant.
Transfer the cooked garlic-onion mixture and chickpeas to a food processor. Blend until well combined, but do not puree.
In a large bowl, mix the chickpea blend with quinoa, eggs, peas, cilantro, and flour. Stir until everything is evenly incorporated.
Scoop the mixture into equal portions and shape into patties. Flatten slightly for even cooking.
Quickly sear each patty on the griddle until lightly browned on both sides.
Transfer to parchment-lined sheet pans and bake until heated through.
Spread tzatziki on the top half of each bun.
On the bottom half, layer lettuce, tomato slices, and a chickpea-quinoa patty.
Add the top bun and serve.