Whenever preschoolers and paint come together, there's sure to be a mess. Prepare your tables for this mess by covering them with plastic garbage bags. Cut the bags so they make one single flat sheet of plastic, and wrap them around the tops of your tables. Tape to the underside of the tables to secure them; depending on the size of your tables, you may need more than one bag per table. Then, when it's time for finger painting to be over, all you have to do is remove the garbage bags and throw them away. The mess on your tables will be gone.
Finger painting doesn't have to involve actual paint. Let your preschoolers use shaving cream instead of paint for an easy way to clean your tables. Squirt gobs of shaving cream directly onto your classroom tables, and let the kids smear away. They can draw little images in the shaving cream, or just smoosh it around the table for a while. When they finish, spray your tables with cleaner and wipe them off. The shaving cream will have actually helped you clean; it removes marker stains from tables.
Have edible finger painting fun by letting kids "paint" with pudding. Give each child a square of clear plastic wrap or waxed paper, and a large spoonful of pudding. When they finish "painting" in the pudding with their fingers, they can simply lick themselves clean.
Pour small amounts of finger paints all over the top of your table (using the trash bags first to protect it). Let a group of children come together to paint on the trash bags. Pour two primary colors on every table to teach kids about color blending at the same time. Mix shaving cream into the paint to make it more tactile and easier to manipulate.
Let kids have a sheet of paper and a small dish with a few blobs of finger paint on it. Let them dab their fingers into the paint and then put fingerprints on the paper. They can make fingerprint flowers by arranging five or six prints in a petal formation, or make fingerprint bugs by using markers to draw antennae and legs after the paint dries from a single fingerprint.
Kinderart.com suggests letting kids paint with an extra hand. Fill a plastic glove with flour or beans, then knot the open end to secure the contents. Let children dip this glove into the paint and paint with the glove's fingers instead of their own for a new experience in textures.