There are two kinds of rice going on in this colorful stir-fry: brown rice and the cauliflower kind. Pineapple gives the whole mix a little sweetness, and cashews add some extra crunch.
In a nonstick skillet, heat olive oil on medium. Add cauliflower, carrot, and bell pepper. Cook, stirring often, until carrot is tender and vegetables have some browning, 8 to 10 minutes. Add cooked brown rice, peas, soy sauce, sesame oil, and garlic powder. Cook stirring continuously, until heated through, 3 to 5 minutes.
Remove from heat. Add pineapple and cashews. (Skip cashews or chop in very small pieces if serving to kids under 4.) Stir to combine. Top with green onion.