What about fruit dipped in strawberry yogurt (pineapple, apple slices, strawberries, etc.)?
If you're feeling adventurous...
Make your own ice cream sundaes! We had A LOT of parent helpers in my son's class. One parent distributed those little ice cream cups, another followed with whipped cream, another with sprinkles, etc. The key to sanity was to keep the kids in the seated and the parents moved around.
Just about anything you put on those fancy toothpicks are a hit with this age. Cheese cubes, turkey, cocktail hot dogs, fruit, veggies, etc.
Finger sandwiches or sandwiches cut with a cookie cutter. Ham and turkey, cucumber and cream cheese, cream cheese and jelly, pb&J--if there are no peanut allergies
If you can eat outside, popscicles are easy. Just make sure you only get one flavor or enough of a variety that you don't have whining (or worse yet, a mutiny!)