Tomatoes are possibly not the best choice; messy and likely to stain white shirts.
My dd1's class got whole raw carrots one morning when I was a parent helper; they were large carrots which still had the ends on and haven't been peeled . They were left untouched because there was an alternative (bananas).
Sadly my dd1 won't eat fruit of any description, so she always just sits and sips her water while everyone else tucks in