The trash can icon is located at the bottom right of the Layers panel.
To delete a layer, do the following.
1) Click and hold the mouse button on the layer to be deleted.
2) Drag the layer to the trash can icon.
3) Release the mouse button.
You can also right click on the layer, and select Delete Layer.
Mac users without a right-click mouse button can press and hold Ctrl when clicking the left mouse button.