I wilt greens with heat all the time, but this method just uses salad dressing. You know how when you dress a salad, it gets all soft and wilty if you let it sit? That's basically what you're doing here, except the stiffer greens like chard or mustard respond well to this treatment: they don't get all slimy like lettuce would.
For this salad, I took a bunch of mustard greens, stripped the leaves from the stems, rolled 'em up and cut them into a chiffonade (fine strips). Then I tossed the greens with too much dressing (a basic olive oil and lemon vinaigrette) and let them sit. After about 20 minutes, they're all wilty and soft, sort of like they'd been cooked. We ate this salad alongside some great beef from our Arrowhead livestock share and a big bundle of shoestring potatoes.
I left this version very simple, but this salad is very nice if you add (after wilting) julienned carrots, peppers or cucumber, scallions or other herbs. And it's really nice if you add toasted pine nuts or pistachios to provide a contrast to the soft, smooth greens.
The one problem with this method is that the greens will continue to wilt and release moisture, so just drain off any liquid if they release too much and everything seems soggy.
This Summer, I am chronicling my first CSA (Community Supported Agriculture) experience. My CSA share is from Arrowhead Farm, a farm based in Newburyport, MA. Each week, I am posting about what was in my share and what I'm doing with it. By way of full disclosure, I won my share through a raffle and am not paying for it. However, Arrowhead did not know I was entered in the raffle, and I received no special consideration because of this blog. I paid for my livestock share.