In a a shallow saucepan, cook the couscous according to package directions. When cooked, remove from heat and fluff into a large mixing bowl. Add the cucumber, tomatoes and red onion.
In a small jar or bottle, add the chopped basil, lemon zest, lemon juice and olive oil. Season with salt and pepper, then shake vigorously until emulsified.
Pour the dressing over the couscous and vegetables; toss until evenly combined.
Sprinkle your zucchini rounds with salt and let them sit for 10 minutes to draw out the water. Blot dry with paper towels.
Heat a thin layer of olive oil in a skillet over medium high heat. Beat the egg in a small bowl and spread the bread crumbs on a small plate.
Dip the zucchini rounds in the egg, then coat evenly with the breadcrumbs. Add to the heated olive oil and pan fry until golden brown, 2-3 minutes. Flip over and repeat.
Spoon the couscous onto a plate or serving platter. Top with the fried zucchini and fresh mozzarella, alternating slices of each. Drizzle with the balsamic reduction and garnish with additional basil, if desired.