Weddingbee boards

As long as the surface is dry, you certainly could use them on the ground and you can use tea lights in them- the same way you use tealights in luminarias.

You will likely need to weigh down the lantern with something so it doesn't blow around. You could hang a small jar filled with sand from the frame of the lantern and place the tealight inside the jar. This will weigh down the lantern and protect the flame.

Paper lanterns were used on the ground here:

http://7layerstudio.typepad.com/7_layer_studio/2009/06/stormy-weather-in-the-hills-of-utah-threatened-to-spoil-the-fun-but-we-were-blessed-with-a-few-hours-of-lovely-non-bluste.html

and here:  http://www.cobistyle.com/index.php/blog/entry/light_and_bright/

Here is an idea to stack paper lanterns into a column:

http://www.diysayhi.com/2009/06/light-columns.html

This is another way to use paper lanterns when you can't hang them, You secure a hollow pipe upright in an umbrella stand, fill the pipe with bamboo garden stakes and attach a paper lantern on the ends.