COOK potatoes in 1 L boiling water in skillet 15 to 18 min. or until tender; drain in colander. Wipe skillet with paper towels. Combine tamarind paste, 1/2 cup water and dressing. Mix 1/2 tsp. each garam masala, ground coriander, cumin and fenugreek, and 1/4 tsp. chili powder. Add to dressing mixture; mix well.
HEAT oil in large skillet on medium-high heat; stir in remaining seasonings. Add potatoes; cook and stir 2 to 3 min. or until evenly coated with seasonings.
ADD tamarind mixture; cook and stir 2 to 3 min. or until bubbly. Remove from heat. Gently stir in fresh coriander. Top wtih onions.
