Place cottage cheese in a blender or food processor, and process until smooth, scraping sides of processor bowl once. Add cream cheese, sugar, and 1 teaspoon vanilla; process until smooth. Pour mixture into a bowl; cover and chill.
Place flour in a medium bowl. Combine milk, oil, 1 1/2 teaspoons vanilla, salt, and eggs, and add to flour, stirring with a whisk until almost smooth. Cover and chill 2 hours.
Place a 10-inch crepe pan or nonstick skillet coated with cooking spray over medium-high heat until hot. Remove skillet from heat. Pour 3 tablespoons batter into pan; quickly tilt pan in all directions so batter covers skillet with a thin film. Cook about 1 minute.
Carefully lift edge of crepe with a spatula to test for doneness. The crepe is ready to turn when it can be shaken loose from the pan and the underside is lightly browned. Turn crepe over; cook 30 seconds on other side.
Place crepe on a towel; cool. Repeat procedure with remaining batter. Stack crepes between single sheets of wax paper or paper towels to prevent sticking.
Spoon 3 tablespoons cottage cheese mixture in center of each crepe; fold sides and ends of crepe over filling to form a rectangle. Place filled crepes, seam sides down, on a baking sheet lined with plastic wrap. (Blintzes may be covered and chilled at this point).
Place a large nonstick skillet coated with cooking spray over medium heat until hot. Place 4 blintzes, seam sides down, in skillet; cook 2 minutes or until lightly browned. Turn blintzes over; cook for 2 minutes. Repeat procedure with remaining blintzes. Serve warm with blueberries, and sprinkle with powdered sugar.
You can make these blintzes ahead for dessert or brunch. Refrigerate the filled blintzes, then sauté them just before you're ready to serve.