Preheat oven to 400° F. Heat 1/2 tablespoon of the oil in a large nonstick skillet over medium heat, then add the cumin and mustard seeds. Cook for 1 minute or until the seeds begin to brown. Stir in the onion and sauté 3 to 4 minutes or until tender.
Stir in the ginger, curry powder, and 1/2 teaspoon of the salt and cook about 45 seconds. Add the potatoes and mash lightly with a fork. Stir in the peas and the remaining salt and cook until the mixture is warmed through, 3 to 4 minutes.
Remove from stove and cool slightly. Place 1 sheet of phyllo dough on a flat surface and brush with some of the remaining oil. Top with another sheet of phyllo and brush again with the oil. Cut the dough into 6 squares.
Place 3 generous tablespoons of the potato mixture into the center of each square and flatten slightly with your fingers. Fold the dough over the potatoes as if you are wrapping a package; brush them with more oil and lay them seam-side down on a nonstick baking sheet. Repeat with the 5 remaining dough squares. Take another 2 sheets of phyllo and repeat the process to form 6 more packages.
Bake for 10 to 12 minutes or until lightly browned. Serve immediately.