Put the dry chickpeas in a bowl and cover with at least 3 inches of water. Soak overnight.
Drain the chickpeas.
Add the drained chickpeas to a food processor with the onion, garlic, parsley, oats, baking powder, coriander, 1 teaspoon cumin, 1 teaspoon of salt, and pepper.
Pulse several times to break down the mixture into a chunky texture.
Form the mixture into 5 patties, place on a baking sheet and place in the fridge to firm up for at least 30 minutes.
15 minutes before preparing the burgers preheat the oven to 350 F.
Spray the patties with cooking spray.
Bake the patties for 10 minutes.
In a small bowl, combine the tahini, lemon juice, garlic granules, the remaining cumin, the remaining salt, and 4 tablespoons of water.
Add the oil to a large frying pan and bring the heat to medium-high.
Add the burgers and cook for 3 minutes on each side being careful when flipping so the burgers hold together.
Slice the tomato.
Assemble burgers on buns with tomato slices, lettuce, and tahini sauce and serve.