You can delete items by first logging in to Give InKind and visiting one of the Give InKind Pages that you are the Organizer of. From there you can click on either Wishlist button:
On the top of the page:
Under your Wishlist items:
Once the Wishlist opens, page organizers have an additional red "X" icon on the product tiles in their Wishlist. Simply click the X to remove an item from your Wishlist.