It's amazing what you can do with some fresh soumen (noodles) from the grocers. I always tend to buy hiyashi chuuka (Chinese-style chilled noodles with various toppings) at the convenience store in the summer, but decided to try my hand at my own this time.
The pack of fresh noodles I bought from the refrigerator section also had a packet of lemon and soy sauce "soup" with it, so all I had to do was boil the noodles for a few minutes, cool them down (you can do this with ice water or put the rinsed noodles in the fridge), and then add my own toppings.
Because the sauce was lemony (though not overpoweringly so), I decided to go for a seafoodish theme - I boiled some shrimp and put them in the fridge, shredded a few pieces of cold krab (with a "k"), sliced some Japanese cucumbers, and made a flat omelet from whisked eggs, milk, and some seasoned salt (which I allowed to chill in the fridge and then cut into thin strips).
Then all you do is toss some of the noodles in a bowl, arrange your toppings, throw on some sliced green onions, pour on the sauce, and you've got a cold colorful treat for hot weather.