My primary students don't start off the year with full "choice". We spend a good amount of time just getting used to seats, procedures, etc. and I also try to do some projects that help me gauge where the students are and what I might need to cover to help them. The first project of the year for K-3rd was a "dot" project for International Dot Day. 2nd graders start off making a painting with a "dot" theme. However they interpret "dot" is up to them. In the second class period, the students have pretty much free reign when choosing other materials to add to their dots. Paper, oil pastels, markers, crayons, and yarn are popular. This year several students took advantage of the paper strips I had cut for weaving and used them in interesting ways.
I know that some more structured teachers probably see these photos and think of the mess... I used to worry about that as well! The students really do a pretty good job of cleaning up their supplies when they finish. That's one reason I call a single table at a time to line up. I don't call a table until they have everything cleaned up and put away correctly.