colnames(data) <- c("var1", "var2")

varnames <- function(var, name){
   return(name)
 }

print(lapply(data, varnames, name=names(data)))

$var1
[1] "var1" "var2"

$var2
[1] "var1" "var2"

$var1
[1] "var1"

$var2
[1] "var2"