Toss the beef cubes with half of the cornstarch, the salt, and pepper. Place the beef in the ActiFry pan.
Drizzle evenly with half of the oil. Cook for 8 minutes or until browned. Transfer the beef to a bowl; reserve.
Add the remaining oil, potatoes, tomatoes, onion, broth, tomato paste, and garlic to the ActiFry pan. Cook for 40 minutes. Whisk the remaining cornflour with enough water to make a smooth paste; stir into the stew and cook for 5 minutes.
Add the reserved beef, any accumulated juices, and ginger; cook for 5 minutes or until beef is warmed through and potatoes are fork-tender.
Stir in the arugula. Adjust seasoning with additional salt and pepper if necessary.