Transfer the steak to a cutting board. Move the pan of tomatoes to the stovetop over medium heat. Add the garlic and cook, stirring gently, until fragrant, about 2 minutes. Add 1 teaspoon water, the parsley, and 1/8 teaspoon salt and stir to combine, scraping the browned bits off the bottom of the pan. Add the spinach, stir just to coat, then divide the spinach and tomatoes between two dinner plates. Slice the steak, divide between the plates, and serve.