Konnichiwa
Welcome to Japan!
Read the book, Badger and the Magic Fan.  Then let the students decorate their own fans.
Make Japanese cherry blossoms.  Show students how to make the trunk of a tree with lots of branches.  Then, give them pink tissue paper to tear and roll into small balls and glue to their tree.
Make the Japanese flag.  A white rectangle with a red circle in the center.
Teach the children some Japanese.  Konnichiwa (hello), sayanora (good-bye), count to 10.
Read How My Parents Learned to Eat, Then practice using chopsticks.  Demonstrate how to use chopsticks and allow the students to pick up small objects like cotton balls and put them in a bowl. 
Websites with more ideas:
Japan Links - lots of links and information
Japan Theme Unit
Downloadable Resources
Lesson plan Database - Japan Studies
Origami Page
Fulbright Fund - Pictures of Japan and teacher resources
Japanese Flag
Map of Japan
Japan Certificate