In a medium shallow bowl, combine 1/2 cup of the sugar with the cinnamon and 1/4 teaspoon salt.
In a large bowl, whisk the flour with the remaining 2 tablespoons sugar, the baking powder, lemon zest and 1/4 teaspoon of salt. Add the eggs, ricotta and vanilla and using a wooden spoon, stir just to combine.
In a large saucepan, heat 2 inches of oil to 365°. Line a baking rack with paper towels.
Using a small ice cream scoop, scoop rounded tablespoons of half the batter into the hot oil. Fry, turning once, until the fritters are golden and cooked through, about 4 minutes. Drain the fritters on the paper towels for 30 seconds, then transfer them to the cinnamon sugar and toss to coat. Repeat with the remaining batter. Serve the fritters hot.