As an action, you can make an Unarmed Strike with the sandals. Creatures hit by the attack must make a DC 13 Strength saving throw or get knocked back 15 feet and get knocked prone. On a success, the creature gets knocked back 5 feet and don't get knocked prone.

If there is a wall or solid surface large enough to cover the creature's size behind them (i.e. doors, scaffoldings, etc.)  when they're knocked back, the creature takes an extra 2d6 bludgeoning damage upon hitting said wall or surface.