Heat vegetable oil in a large wok or skillet over medium-high heat until shimmering.
Add diced carrots to the wok and stir-fry for 2 to 3 minutes until slightly softened.
Incorporate minced garlic and ginger, sautéing for 30 seconds until aromatic but not browned.
Add pineapple chunks and frozen peas to the skillet, cooking for 2 minutes until the pineapple begins to caramelize at the edges.
Add the chilled cooked quinoa to the mixture, using a spatula to break up any large clumps.
Pour in the soy sauce, toasted sesame oil, and turmeric powder, stirring constantly to ensure the quinoa is evenly coated and vibrant yellow.
Stir-fry the mixture for 3 to 5 minutes until the quinoa is heated through and develops a slightly crispy texture.
Fold in the sliced green onions and roasted cashews.
Season with black pepper and additional soy sauce if required, then serve immediately.