My hubby made this for me last night and it hit the spot as well as any burger ever did! I apologize for the lousy photo. It is much more impressive in real life.
Slice a tomato in thirds-in the round so you have a top, middle and bottom slice. Thinly slice a piece of cuke and cover small plate with these slices. Put the bottom 1/3 of the tomato on the plate, cut side up. Put a few onion rings on the tomato. Place the middle 1/3 on the onion rings and add more very thinly sliced cukes on top of this. Add the top to the tomato. Mix the dressing to your specifications. Pour over the top of your beefy tomato and garnish with parsley.