Place peas in a medium-size saucepan; cover with water and rinse. Drain and repeat 3 or 4 times until water is clear. Add 4 cups of water and bring to a boil over medium-high heat. Skim the foam off top and discard. Add potatoes and turmeric to peas, stirring once or twice. Reduce to medium-low and cover. Simmer stirring occasionally, until peas are tender but still firm-looking and potatoes are cooked, 20 to 25 minutes.
Heat a small skillet over medium-high for about 2-4 minutes. Sprinkle chilies, coriander, and cumin into pan. Toast spices, shaking pan frequently, until chilies blacken and spices are aromatic. Transfer to a blender and add tomatoes; puree until smooth. When peas and potatoes are cooked, add spice mixture, cilantro and salt. Vigorously boil curry uncovered for 12-15 minutes. Stir in green peas and serve. Makes 6 servings.
Approximate Nutrient Analysis per serving (not including salt to taste):
180 calories, 1 g fat, 0 g saturated fat, 0 mg cholesterol, 500 mg sodium, 35 g carbohydrate, 9 g fiber, 6 g sugar, 9 g protein