- Green papaya is an unripe papaya, the flesh is very firm, and greenish-white in color (not orange-red, soft and sweet like a ripened papaya). Green papayas are available in most Asian (especially Thai, Cambodian and Vietnamese) grocery stores. Check your local Asian shopping center. If you can't find unripe green papaya, you can substitute unripe mango (very hard, woody and sour to the taste or very firm, unripe zucchini, or you could mix the two. If you go with these, follow same directions as with papaya). - Thai fish sauce (nam pla) is available in most grocery stores. When you first open the container and smell, it may come across as a bit fishy, but trust me, it is often the most important ingredient in S.E. Asian cuisine. - Peanuts: I prefer to toast my own, it's far easier than it sounds. Heat a large fry pan over high heat for 1 minute, then add whole raw, skinless peanuts. Turn down the heat to medium-low and keep constantly stirring and flipping the peanuts in pan, make sure you don't scorch them, but it is fine for them to get browned little heat (toasted) spots. If you smell acrid-smoke odor, then you are burning them, the aroma should smell almost like fresh peanut butter. Should take around 7 to 10 minutes to cook them. After 7 minutes take a few nuts and let them cool, taste them, if they are crunchy then done, if still a little soft and raw tasting after cooling then toast some more. You can toast a pound in advance and store them in a zip lock bag or glass jar for a couple of months or so. Once you start toasting your own peanuts you'll never buy jarred ones again, but if you don't want to toast your own then you can use unsalted, dry roasted peanuts. For the papaya salad, loosely crush the nuts. I usually do this by placing nuts in a resealable plastic bag or in between a few layers of paper towel. Then roll with a rolling pin or smash with a mallet. Again, loosely crushed, NOT crushed to point of being crumbed or to near peanut butter state. - Dried shrimp: Some western pallets find this a little too exotic and fishy to the taste, but for me Sum Tum isn't Som Tum without dried shrimp. It you are a wee bit leery about using the dried shrimp then just add a tablespoon or 2, or serve in side dish and let diners add them to their own plates. - Thai chiles: These are the small, 1-inch long red and green peppers that are VERY hot. If not available you can use jalapeno or habanero peppers. I mince chiles with the seeds. Traditionally Sum Tom or papaya salad is a very spicy dish in Thailand.