Preheat the oven to 400°F (200°C) and line a baking sheet with a silicone baking mat or parchment paper.
In a small bowl, combine 1 cup ricotta, 1 tablespoon chopped parsley (or substitute herb), a pinch or two of kosher salt, several turns of freshly ground black pepper, and grated Parmesan to taste; mix and adjust seasoning as needed.
Spoon about 1 teaspoon of the ricotta mixture into the center of a wonton wrapper.
Roll the wrapper into a tight tube and place seam-side down on the prepared baking sheet; repeat with remaining filling and wrappers.
Lightly brush each roll with olive oil and bake for 10–12 minutes, until the edges are crisp and the centers have puffed.
To serve, spoon tomato sauce onto plates, arrange the mini cannelloni on top, and garnish with parsley leaves, shaved Parmesan, and a grind of black pepper.