Melon, Cucumber and Tomato Salad When it's as hot as it has been in so many parts of the country lately, hydrating foods like cucumbers are especially appealing. Cucumbers are a very good source of vitamin C and caffeic acid, compounds that help the body prevent water retention, a problem that many of us suffer from on hot summer days. I reach for cucumbers most often at lunch, when I want simple, refreshing vegetables to eat with cottage cheese or throw into a sandwich. I'll sometimes make a big batch of tangy cucumber raita and enjoy it for lunch throughout the week, either on its own or packed into pita bread. This week's salads are great for lunch or dinner. The Israeli couscous and cucumber combo could even be served as a light main dish. Lately I've been buying Persian cucumbers more than any others. I like the small size, the absence of big seeds and the thin skin. I also love the locally grown Japanese cukes I'm buying at the farmers" market. At other times of year I settle for the hothouse European variety, but they can't compare with what you can get right now at your farmers" market. Seek out unwaxed cucumbers so you won't need to peel them and can benefit from their skin, a rich source of fiber and a good source of potassium and magnesium. Years ago I took a weeklong cooking course at Le Cordon Bleu in London. The chef giving the demonstrations would end each one by saying, "It's very good to eat." I was dubious when she presented this salad, but she was right! Melon and cucumber go well together in this refreshing combination; they're closely related botanically. 1 European cucumber, peeled if desired and cut in medium dice 1 pound ripe tomatoes, peeled and seeded if desired, cut in thin wedges or diced 1 small ripe honeydew melon or cantaloupe, peeled and cut into 1-inch dice or shaped into melon balls 2 to 3 tablespoons Champagne vinegar or sherry vinegar 1 tablespoon fresh lime juice 1 teaspoon mild honey, like clover, or agave nectar 4 tablespoons grapeseed oil, rice bran oil or canola oil 1 tablespoon chopped flat-leaf parsley 1 tablespoon chopped fresh mint 1 tablespoon chopped chives Fresh watercress for garnish (optional) Put the cucumbers in a colander set in the sink or a bowl. Sprinkle with salt and let drain for 30 minutes. Meanwhile, prepare the other ingredients. Toss the cucumbers, tomatoes and melon together in a bowl. Whisk together the vinegar, salt to taste, lime juice, honey and oil and toss with the fruit and vegetable mixture. Cover the bowl and refrigerate for 1 to 2 hours. Just before serving, toss with the herbs. Line plates with watercress if desired. Taste the salad, adjust the seasonings and serve over the watercress. Advance preparation: You can make this through Step 2 several hours ahead. Because of the salt, the vegetables and fruit will give off a lot of water, so if you don't want the salad to be too juicy, salt shortly before serving. Nutritional information per serving: 166 calories; 10 grams fat; 1 gram saturated fat; 7 grams polyunsaturated fat; 1 gram monounsaturated fat; 0 milligrams cholesterol; 21 grams carbohydrates; 3 grams dietary fiber; 36 milligrams sodium (does not include salt to taste); 2 grams protein