Heat the olive oil in a large pot or Dutch oven over medium-high heat. Add the bacon and cook, stirring occasionally, until browned and crisp, about 7 minutes. Add the onion and continue cooking until softened, about 2 minutes. Stir in the escarole, 1/2 teaspoon salt and a few grinds of pepper. Cook until the escarole is completely wilted, about 3 minutes.
Meanwhile, bring a large pot of salted water to a boil. Add the gnocchi and cook as the label directs. Reserve 1/2 cup cooking water, then drain the gnocchi and add to the pot with the escarole mixture. Add the reserved cooking water and stir to coat, about 1 minute. Stir in the tomatoes, parmesan and parsley; season with salt and pepper.