Click random item at the given range

at 1.
not really clear what you mean by random item.
If it is an image whose contents might change from time to time, then you cannot use it to search for.
You have to use some fixed image in the neighborhood and click using any of the offset features.

at 2.
I guess we are talking about Python scripting:
http://docs.python.org/2.6/library/datetime.html

1. I got a bunch of files. I need to pick 1 random file to delete it. The files name will be random when someone's upload it into the system.

you might send me a screenshot silently to my mail (https://launchpad.net/~raimund-hocke) with some comments on what you want to achieve.

2. I got the general idea.

import time

time.strftime('%d-%m-%Y')

to call the time now. (right? this is what I've been using)

but I still don't know how to ask sikuli to select/type tomorrow's date?

click(pattern("some-reference-pic.png")targetOffset(x,y)))
type(*tomorrow's date* + Key.TAB) #this is where I want sikuli to type tomorrow's date
type(*tomorrow's date*) #same with this

many thanks.

ok i already got this

my script

import datetime

tomorrow = datetime.date.today() + datetime.timedelta(1)

click(Pattern("from.png").similar(0.75).targetOffset(54,0))
type(str(tomorrow))
click(Pattern("to.png").targetOffset(39,1))
type(str(tomorrow))

but this is type as format Y-m-d

I need a format d-m-Y

Thanks RaiMan, that solved my question.