Make the batter: Combine the milk, water, eggs, flour, sugar, and salt in a blender. Blend on medium speed for 15 seconds, until the batter is smooth and lump-free. Scrape down the sides of the blender and pour in the melted butter. Blend it again for a few seconds just to incorporate the butter. Refrigerate the batter for 1 hour to let it rest.
Make the filling: In a small bowl combine the ricotta cheese, cream cheese, egg, confectioners' sugar, and zest and blend until smooth. Chill until ready to use.
Make the sauce: Combine the strawberries, sugar, water, cornstarch, and zest in a small pot over medium heat. Bring to a simmer and stir gently until the berries release their natural juices. The consistency should remain a bit chunky, it will thicken up when it cools down.
Make the crepes: Put an 8-inch crepe pan or nonstick skillet over medium heat and brush with a little melted butter. Pour 1/4 cup batter into the pan and swirl it around so it covers the bottom evenly; pour back any excess. Cook until the crepe batter sets and the bottom is lightly browned, about 2 minutes. Use a heatproof rubber spatula to loosen the crepe and flip it. Cook it on the other side for about 1 minute. Slide them onto a plate and continue making the crepes until all the batter is used. Cover the stack with a towel to keep them from drying out. Makes about 10 crepes.
Assembly: Preheat the oven to 400 degrees F.
Spoon 1/4 cup of the cheese filling along the lower third of the crepe. Fold the bottom edge away from you to just cover the filling; then fold the 2 sides in to the center. Roll the crepe away from you a couple of times ending with the seam side down. Put an ovenproof skillet over medium heat and brush with melted butter. Pan-fry the blintzes top side down until crisp and golden, about 2 to 3 minutes. Flip them over, transfer the pan to the oven, and bake for 10 minutes so the cheese mixture sets. Using a spatula, transfer the blintzes to serving plates. Spoon the strawberry sauce on top, dust with confectioners' sugar, and serve immediately.