Pick the leaves from the stems. Discard any tough parts of steams. Under cold, running water, wash and drain well. Steam kamote leaves for about 1 to 2 minutes or until just wilted. Alternatively, in a pot over medium heat, bring about 2 cups of water to a boil. Briefly dip leaves in the boiling water for about 10 to 20 seconds or until just wilted. Quickly plunge leaves in iced water for about 30 to 40 seconds or until cold. Drain well.
In a bowl, combine kamote leaves, tomatoes and shallots.
In small bowl, combine vinegar, garlic, fish sauce, oil, sugar, and salt and pepper to taste. Let stand for about 10 to 15 minutes to allow flavors to meld.
Drizzle dressing over salad and gently toss to combine.