The best way for preschoolers to learn about something -- and get interested in wanting to continue learning about it -- is to let them see it with their own eyes. If possible, bring a terrarium into the classroom showing your preschoolers the kind of habitat in which salamanders live. Explain how the salamander needs to live in a damp place to keep its skin wet and what kind of food they eat (earthworms, slugs and snails). Though touching the salamander may be harmful to it, have a slimy substance on hand to illustrate the feel of their skin.
Preschoolers especially love to play with Play-Doh, but at the end of the day, it must be squished back into its container. Use modeling clay that will harden after baking and get the preschoolers to make salamanders they can keep. Print out pictures of different kinds of salamanders from all over the world for them to use as reference. When the children are finished sculpting, bake the clay according to the package directions, and let your preschoolers paint their salamanders. Their sculptures can be placed around the room as class decorations or taken home.
Preschoolers have the fine motor skills to safely operate scissors and use glue -- stick glue tends to be less messy. Bring in nature magazines for the children to look through and have them cut out pictures of things salamanders need to survive. For instance, a child may cut out big trees to provide shade for the salamanders, a pond for it to live by and snails for it to eat. Move around the room answering questions and reminding the children about the types of places salamanders live.
Preschoolers enjoy self expression and the ability to freely create. Talk to your preschool class about a painter named Pablo Picasso, and show them pictures of the type of artwork he created. Then ask them to make a Picasso-style salamander painting. Explain that like Picasso, they can put the eyes where the toes would go or a tail from its head. Not only will this teach your class about Picasso, but your preschoolers will have a blast making their silly salamanders and learning where parts of the amphibians' anatomy go and don't go.