According to Kicks HI in collaboration with NMLS World, Chee! means:
The state of being stimulated, refreshed, or elated.
An exclamation of excitement that really has no real meaning said down here in Hawai’i. If you know, you know.
And I’ll take their word for it, especially with awesomely designed duds emblazoned with Chee! Everyone needs some Chee! in their lives, and I doubt there can there be too much Chee!