Add sunflower oil to a medium-sized saucepan. Quickly saute the garlic and ginger over medium-high heat until lightly browned, about 3 minutes. Add the scallions and saute for an additional 30 seconds.
Pour in Dei Fratelli Petite Diced Tomatoes and tamari and reduce slightly, about 5 minutes. Add the broth and bring to a boil. Reduce to a simmer and cook for 8 minutes.
Pour over soba noodles and garnish with roast beef, onion, pepper, scallions, and pickled ginger.