1To make vinaigrette, in small bowl, mix oil, vinegar, cilantro, 1/2 teaspoon salt, garlic and pepper with wire whisk until well blended.
2In 3-quart saucepan, heat water and salt to boiling. Add cactus. Heat to boiling; reduce heat. Boil uncovered 5 minutes; drain. Immediately rinse with cold water, or plunge into large bowl of ice and water; drain. Repeat rinsing and draining twice.
3In large bowl, mix cactus, zucchini and bell pepper. Add vinaigrette; toss to mix.