Whisk the ricotta, heavy cream, and lemon zest in a mixing bowl until combined. Add in the ¼ teaspoon of salt and a few cranks of black pepper. Taste the ricotta and adjust the seasoning as necessary.
Preheat the oven to 425°F. Lay the baguette slices out on a sheet pan and drizzle each with a little olive oil. Toast until they are golden brown, about 6 minutes.
In a bowl, combine the olives, ¼ cup olive oil, red pepper flakes, lemon juice, and parsley. Season with salt and pepper to taste.
Spread the ricotta mixture over the toasted baguette slices. Add a spoonful of the olive mixture to each crostini, then drizzle with olive oil and season with freshly cracked black pepper and flaky sea salt.