Bring the water to boil in a large saucepan. Squeeze the lemon half into the water and add the lemon half to the water, too. Add the cauliflower to the pan; cook 3 minutes. Drain and discard the lemon half.
Heat the oil in a large nonstick skillet over medium heat. Add the cauliflower to the pan, cooking 12 minutes or until soft, stirring occasionally. Add the garlic and cook 30 seconds or until lightly browned.
Transfer the cauliflower mixture to a large bowl. Add the parsley, lemon juice, capers and salt; toss well.