Preheat a large heavy bottomed pan (preferably cast iron) over medium heat. Toss in the cashews and dry toast them for about 5 minutes, flipping occasionally. They should be slightly browned in some spots, but it’s okay if they’re unevenly browned, you don’t have to be too precise about it. Transfer cashews to a large plate.
Now we’re going to sear the green beans. Turn the heat on the pan up to medium-high. Add the green beans, a scant tablespoon of oil and a dash of salt. Cook for 3 to 5 minutes, until the beans are bright green and seared. Transfer beans to the same plate as the cashews.
Add the onions to the pan along with another tablespoon of oil and a dash of salt. Toss for about 3 minutes, until onions are slightly charred but still firm. Add the garlic, ginger, coriander and red pepper flakes, and toss for 30 seconds are so, being careful not to burn.
Add another tablespoon of oil and about half of the cold rice. Toss to coat, then add in the remaining rice, tossing once again. Cook for about 3 minutes, tossing often, until warmed through.
Add another tablespoon of oil and about half of the cold rice. Toss to coat, then add in the remaining rice, tossing once again. Cook for about 3 minutes, tossing often, until warmed through.
Add the string beans and cashews, mangoes, basil leaves and lime juice. Cook just until mangoes are heated through and basil is wilted, a minute or two. Taste for salt (don’t add more tamari, just add salt if it needs it) and serve, garnished with cilantro if you like, and with a bottle of Sriracha close by.