Pour olive oil into a heavy skillet over medium heat, add bacon, and cook until almost crisp, 5 to 8 minutes. Turn off heat. Hold a paper towel with tongs and mop up excess bacon grease with the paper towel, leave about 2 teaspoons bacon grease in the skillet.
Stir minced garlic and lemon zest into bacon in the skillet and let cook in residual heat until fragrant, 2 to 3 minutes. Stir creme fraiche into bacon mixture.
Bring a large pot of salted water to a boil and stir in 2 cups of ditalini. Cook till tender, about 8 minutes. Drain and add pasta to the skillet. Stir pasta thoroughly into bacon and creme fraiche mixture.
Return skillet to medium heat. Add tomatoes; cook and stir until slightly softened, about 1 minute. Mix in arugula, stirring until wilted, about 30 seconds, and turn off heat.
Season with salt, black pepper, and cayenne pepper. Stir again and garnish with Parmesan cheese.