Place potatoes and water in 2-quart casserole; cover.
Microwave at HIGH (100%) until fork-tender, 12 to 15 minutes, stirring after half the time.
Let stand 5 minutes.
Drain and set aside.
Place margarine in 2-cup measure.
Microwave at HIGH (100%) 1 to 1 1/2 minutes.
Stir in remaining ingredients.
Pour over potatoes.
Toss to coat.