Pulse the macadamias in a food processor a few times to break them up.
Add the almond milk, agave, coconut oil, vanilla and salt. Blend until relatively smooth, but don't overdo it or the mixture may turn into nut butter. It should be thick and creamy with just a little graininess.
Transfer the cheese to a mixing bowl. Add the lemon zest and juice and mix well. Taste and add more lemon juice if you like. Cover and refrigerate until ready to use.
Combine the blueberries, sugar, cornstarch and cold water in a saucepan. Stir until the cornstarch has dissolved.
Set the pan over medium heat. Cook, stirring often, until the sauce is thick and glossy and the blueberries have burst and released their juices, about 10 to 15 minutes. Keep warm until ready to serve.
Place ⅓ cup macadamia cheese in the lower third of a crepe. Fold the bottom up and over the filling. Fold in the left and right sides so the cheese is tucked in snugly. Roll up the blintz like a burrito. Repeat with the remaining crepes.
Preheat a cast-iron or nonstick pan over medium-high heat. Add enough coconut oil to coat the bottom.
Place the blintzes seam-side down in the pan. Cook until golden brown, about 2 to 3 minutes per side.
Serve warm, sprinkled with powdered sugar and topped with blueberry sauce.
