In a large bowl, combine zucchini, onions, eggs, matzo meal and salt and stir to combine. Heat ¼-inch oil in a large sauté pan over medium high heat. Drop by 2 tablespoons full and lightly press down to flatten. Fry for about 4 to 6 minutes per side or until nicely browned. Remove and drain on paper towels. Continue with remaining batter.
In a small bowl, combine yogurt, dill, cucumber, lemon juice and salt and stir. Serve Tzatziki alongside Latkes.