Combine water and salt in saucepan; bring to a boil. Add couscous.
Cover and remove from heat. Allow to stand for 5 minutes.
Coarsely chop the garlic in a food processor. Add the mint and pulse until finely chopped. Add the chickpeas and remaining salt and pulse until coarsely chopped.
Uncover the couscous and fluff with a fork.
In a large bowl, combine couscous, chickpea mixture, eggs, and lemon zest, mixing until well combined.
Press the couscous mixture into a ¼ measuring cup, smooth the top, and invert the measuring cup to release the cake onto a tray. Repeat with the remaining couscous mixture to make 8-9 cakes.
Refrigerate for 10-15 minutes to allow the mixture to set.
Heat 1½ tablespoons oil in a large skillet over medium heat until simmering.
Add about 5 of the couscous cakes to the skillet; use a spatula to lightly flatten to about ¾-inch thickness.
Cook, flipping once until the patties are crisp and golden brown on both sides, about 3-5 minutes per side. Transfer the cooked patties to a paper and keep warm. Add the remaining 1½ tablespoons olive oil to the skillet and cook the remaining cakes the same way.