Putting together a great salad is not quite as simple as starting with quality fresh greens and vegetables and dressing them, but it is a very good start. The rest lies in making sure that you offer enough textural and flavor contrast that the salad doesn't get pushed to the side of the table as an accompaniment—something boring to keep you occupied between bites of the main course. In that sense, when I plan a salad, I try and make sure that it's its own side dish, if you get what I mean.
The key to this salad is the pickled vegetables. It starts with chunkily-cut cucumbers and sliced onions pickled in a simple mix of equal parts vinegar and water with some sugar added. This makes for a nice, light pickle that's punchy and bright, but tame enough that you can eat it by the forkful without pursing your lips so hard you pull a muscle. I like to think of light pickles like that as vegetables that have their dressing already built in.
Next, I added some hon-shimeji mushrooms to the same liquid. Mushrooms, with their great absorbency, make for awesome pickles. They suck up flavor like a sponge and release it just as easily. Their soft-but-firm texture is also nice agains the ultra-crunchy cukes.
For freshness and a burst of sweetness, I went with snap peas, simply blanched in salted water. They're super sweet this time of year, and unlike, say, English peas or asparagus, they tend to keep their sweetness for several days after being picked. They're one of the most forgiving fresh spring vegetables I know.
With all that great pickling liquid, the dressing for the rest of the salad—some nice red oak lettuce that Jamie picked up from the Union Square Greenmarket—is easy. Pickling liquid, along with a bit of mustard and good extra virgin olive oil.
I always like to have some sort of salty burst in my salad—something to really whack your mouth in the...mouth (I guess)—and that burst is often cheese. In this case, an extra-sharp aged Pecorino that's crumbled fine enough that every bite oughta get a burst or two.
You'll probably want to serve this salad with other food, but you don't need to. It's got a personality of its own.