First, make the blueberry sauce. In a small bowl, combine the lemon juice and cornstarch and set aside. In a medium saucepan, combine the blueberries, sugar, and water. Bring to a boil over high heat. Reduce to a simmer and stir in lemon juice and cornstarch mixture. Stir until the sauce thickens slightly. Cover to keep warm and set aside.
In a large bowl, whisk together flour, sugar, baking powder, baking soda and salt. In a medium bowl, whisk together ricotta cheese, egg, egg whites, lemon juice, lemon zest, and canola oil. Gently fold this mixture into the dry ingredients until flour disappears. Don't over mix. The batter will be thick.
Heat a griddle or a nonstick skillet over medium heat. Spray with cooking spray. Drop about 1/3 cup of batter onto the hot griddle or skillet. Cook the pancakes until browned on the underside and beginning to set, about 2 minutes. Flip and cook the pancakes on the other side, about two minutes longer. Continue making pancakes until batter is gone. Serve warm with blueberry sauce.