Cook the squash, covered, in a small amount of boiling water for 3 minutes. Set aside. Grill chicken on an uncovered grill directly over medium-hot coals for 15 to 18 minutes or until tender and no longer pink; turn chicken halfway through grilling time.
Meanwhile, generously brush the squash, zucchini, and sweet pepper strips with melted margarine or butter to prevent vegetables from sticking to grill rack. Lay vegetables on grill rack perpendicular to the bars so they don't fall into coals. Cook vegetables on grill with the chicken until tender and slightly charred, turning occasionally (about 10 minutes for squash, 8 to 10 minutes for peppers, 5 to 6 minutes for zucchini).
Line four salad plates with savoy, endive, and/or cabbage leaves. Arrange chicken and vegetables on plates. Serve with Red Salsa or favorite salad dressing. Makes 4 servings.