This is a food item, consuming it (via right click) will replenish your food and water. This item has some anti-radioactive properties, consuming it will lower your radiation level. It will also provide minor healing.
A can of beans is a food item that is non-craftable and is primarly used to restore Calories and reduce Radiation.
The beans can be consumed by putting it into the Hotbar and pressing the specified key of 1-6. Or from anywhere in your Inventory by hovering your mouse over the item and then clicking on it with your right-mouse button after which you can select the Consume option.