A composed salad is the obvious thing to make when the fridge is full of Easter Eggs. Salad Niçoise is one version that I especially love, there is something magical about the combination of vinaigrette, hard boiled egg and canned tuna. They work phenomenally well together.
But the type of tuna is important - Mark Bittman gets it right here, in his recipe on p. 122 of How to Cook Everything: the tuna must be canned and packed in oil. The best canned tuna I've ever eaten came from a friend who had caught the fish and canned it himself in little glass jars. It was like no tuna I'd ever eaten before - more flavorful, less fishy and incredibly delicious. Island Trollers, a fishing company based on the beautiful Whidbey Island in Washington state, sells the next closest thing I've found since that jar.
--- After dinner follow up:
A composed salad of any sort has to built around the ingredients one has on hand. So this one had only potatoes, lettuce, tuna and eggs. We had no green beans and no cherry tomatoes (any other type with Salad Niçoise just seems wrong). The dressing was made with 3Tablespoons olive oil, 1 Tablespoon champagne vinegar and 1 teaspoon dijon mustard, plus salt and pepper.
My kids loved it! They even tried (and finished) their potatoes with extra vinaigrette, after I said no to ketchup. "Just try it this once," I wheedled, "you might like it." And they did!