Place a small skillet over medium-high heat and add the oil. Add the curry leaves, mustard seeds, coriander, and salt and toast for 1 minute. Stir in the soya beans and cook for about 3 minutes. Let the mixture cool.
Put the papaya chunks into a salad bowl along with the rice and cooled soya bean mixture. Add salt, pepper, and lime juice and toss well. Taste and add more salt, if needed.