I've had a few of those lately, and though they're not specifically seasonal, they will be (by later in the season) and they'll bear repeating in August when tomatoes and beans are peaking.
Halibut baked in parchment is fantastic: the fish stays moist and mild, gently flavored by rosemary and olive oil. Last night I served it like a semi-nicoise, atop a bed of arugula, blanched haricot verts quickly sauteed with more olive oil and some chopped shallots, a few oil cured black olives, some just-hard-cooked eggs (9 minutes in simmering water will do it) and a squeeze of lemon and a drizzle of more good olive oil on top. Alongside, I served one of the great workhorse condiments you can make: salsa verde. I use Suzanne Goin's recipe, which calls for parsley, mint and marjoram along with the more esoteric: salt packed capers and anchovies. (Locally, you can get both of the latter at Rubiner's Cheesemongers in Great Barrington.)
The idea for a halibut nicoise comes from Goin, too, but my preparation of the halibut is different, and comes from another wonderful and favorite cookbook, I Am Almost Always Hungry
To accompany the nicoise, I made a potato and tomato gratin, also by Suzanne Goin. This recipe is unfortunately not available online, but hopefully you've already broken down and purchased Sunday Suppers at Lucques