Prepare an ice bath of cold water and ice cubes then set aside. In a small bowl, make the dressing mix by combining the soy sauce, fi sh sauce, white vinegar, sugar, tabasco, sesame oil and salt, mix well and set aside. Bring a medium size pot of water to a boil over high heat. Add the string beans to the pot and blanch for 1 to 2 minutes or until al dente, drain and then place into the ice bath to stop the cooking process. Once cool, strain and set aside. In a large bowl add string beans, sliced cucumbers, tomatoes, grapefruit, cilantro, mint and dressing and mix together well. Chill salad in the refrigerator for 15 minutes and toss before serving. This is a great refreshing salad for a hot summer day!