Kra Pao is the spicy kind of basil, as opposed to Thai basil. Look for a lighter green, somewhat crinkled leaf compared to Thai basil. You can use Thai basil if it's all you can get, and it will taste just fine, but will be less spicy. You can make this recipe using any kind of meat, or even just eggplant for a vegetarian version. Vary the amount of chili paste and chilies to control the heat. I often just leave out the chiles. Red or green chilies are both fine.