Bring a large pot of heavily salted water to a boil and fill a large bowl with ice water. Drop green beans into boiling water and cook until just tender, about 3 minutes. Drain and immediately plunge into ice water. Once cool, remove onto paper towels to absorb excess water.\nMeanwhile, in a small bowl whisk together 1 Tbsp Southeast Asia sauce and mayonnaise. Set aside.\nHeat oil in a large skillet over medium-high heat. Once shimmering, add blanched green beans and cook until starting to brown, about 2 minutes. Add sliced shallots and sauté until softened, about 1 minute more. Pour in remaining 1\/4 cup Southeast Asia sauce and stir until green beans are well coated and heated through, about 2 minutes. Add cashews and toss to coat.\nPour cooked green beans into a serving bowl and drizzle with Southeast Asia mayonnaise. Serve warm.