Instead of sandwiches you could try pita pockets? I buy the mini pita bread, cut them in half and let dd stuff them herself. There's a platter of luncheon meats or chicken cubes, cheese slices, cucumbers or shredded lettuce or whatever veggie I have available. Takes no time to prepare at all 5 min max. DS is beginning to eat them as well instead of picking them apart. lol
Oh, and we must have a pickle with all sandwiches or pita pockets.