1. Instead of putting everything into one large wonton cup, make several smaller ones (as KYHeirloomer suggested, using minimuffin tin), put a dab of tuna into each, and top each one with something different: avocado on one, cucumber on another, caviar on a third. Or put the other stuff in the cup first and top with tuna. In any case, do not fill all in the same order. Stick a long piece of chive in each and have the tips meet over the space in the center of the cups.
2. Deconstruct it: Variation of presentation used at Match Uptown (iirc): on the plate, make a circle of overlapping very thin cucumber slices. Place ring mold over center of circle, fill with tuna, pack down. Top with diced avocado. Remove ring mold. Sprinkle caviar around the outside edge of the cucumber circle. Cut wonton skins into two triangles; deep-fry or bake to crisps. Stick two wonton crisps into the top of the tuna/avocado mold.
3. Another deconstruction: Mold tuna into a puck or a pyramid on plate. Make crisps of whole wonton wrappers. Dice avocado, slice or dice cucumber. Arrange crisps, avocado, cucumber on/in/around tuna. Sprinkle caviar.
"Notorious stickler" -- The New York Times, January 4, 2004