In a 12-inch skillet cook onions in hot oil over medium heat for 5 minutes or until just beginning to soften, stirring occasionally. Add green beans, rosemary, garlic, and salt. Cover and cook about 10 minutes more or until beans are crisp-tender. Meanwhile, halve and pit peach; cut into slices. Remove bean mixture from heat and toss in peach slices and lime juice.
Transfer green beans to serving bowl. Serve either hot or chilled. Makes 4 servings.