In a small bowl, combine the lemon juice, sour cream, and mint. Slowly whisk in the olive oil. Season to taste with salt and pepper.

Put the couscous and 1 teaspoon salt in a medium bowl. Add 1 cup boiling water to the couscous, cover the bowl with a pan lid or plate, and let sit for 4 to 5 minutes.

Coarsely chop the garlic in a food processor. Add the parsley and pulse until finely chopped. Add the chickpeas and 1 teaspoon salt and pulse until coarsely chopped.

Uncover the couscous and fluff with a fork. Stir in the chickpea mixture, eggs, and lemon zest until well combined. Press the couscous mixture into a 1/4-cup measure, smooth the top, and invert the measuring cup to release the cake onto a plate. Repeat with the remaining couscous mixture to make 9 cakes.

Heat 1-1/2 tablespoons of the vegetable oil in a large skillet over medium heat until shimmering hot. Add 5 of the couscous cakes to the skillet and use a spatula to lightly flatten the cakes so they're about 3/4 inch thick. Cook, flipping once, until crisp and golden brown on both sides, 2 to 3 minutes per side. Transfer to a paper-towel-lined plate. Add the remaining 1-1/2 tablespoons vegetable oil to the skillet and cook the remaining cakes the same way.

In a large bowl, toss the spinach, artichokes, and tomatoes with about three-quarters of the dressing. Season to taste with salt and pepper and divide among 3 large plates. Top each salad with 3 couscous cakes, sprinkle each salad with feta, and drizzle with the remaining dressing.