Brush an 8-by-8-2 1/2-inch glass baking dish with oil. Bring the water and kosher salt to a boil in a heavy, medium saucepan over medium heat. Add the polenta using a whisk to incorporate. Reduce the heat. Let simmer for about 10 minutes, stirring frequently. Add the cream, using a whisk to incorporate. Cook until the consistency is soft and thick, about 10 minutes. Remove from the heat and add the Parmesan cheese, using a whisk to incorporate. Pour the polenta into the prepared baking dish and spread evenly into the dish using a large spatula or the back of a large spoon. Refrigerate until chilled. To make the salsa: Mix the sun-dried tomatoes, basil, balsamic vinegar, garlic and pepper together in a small bowl.

To Assemble: Preheat the oven to 300 degrees F. Trim the edges of the polenta and cut into 36 squares. Top each square with 1/2 teaspoon of the salsa. Place on a foil- or parchment paper-lined baking sheet. Bake until slightly warm, 8 to 10 minutes. Serve warm.

Do-Ahead Tips: The polenta and the salsa can be prepared up to two days in advance. The squares can be assembled up to one day in advance. Bake as directed.