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 teaspoon 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 1/4 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 1 1/2 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 3/4-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 1 1/2 tablespoons olive oil to the skillet and cook the remaining cakes the same way.