A cold soup like Gazpacho would work well. I don't have my recipe here with me, but it consists of a tomato base (not tomato sauce, but like canned tomatoes) with garden veggies, some chiles, garlic, onion, maybe some zuchini, definitely has to have cilantro. You can add your favorite hot-sauce, or leave the cold-heat out. This is cooked until the veggies are jsut barely tender, then chilled and served cold.
Fruit salads are always a hit. Try making them with colorful berries, mellon-balls, and citrus. For interesting flavor, add thinks like sliced star-fruit, or mangoe, pineapple, even kiwi or lo-quats, lychee fruit, etc. Flavor with nutmeg, and cinamon. Use Splenda to lightly sweeten.
And great baked beans are very good when served cold, as is cold spagheti, where the sauce is chilled with the noodles, and all mixed together.
Seeeeeeya; Goodweed of the North