If I would have the choose between a main dish or starter, I will surely take a starter, or a few starters instead of a starter and main dish ;-).
Simple and pure, although not ideal for my ecological footprint, is carpaccio or sashimi of raw salmon and tuna.
For 2p 100 grams of each in combination with a simple dressing of lemon, olive oil, mustard, a bit of honey, pepper and salt is so delicious! Only one condition, the fish has to be super fresh.