Add the cauliflower florets to a food processor and pulse just until the cauliflower resembles rice. (Do not overprocess it or it will be mushy.) Set the cauliflower rice aside.
Heat a large nonstick sauté pan over medium-low heat. Coat it lightly with cooking spray then add the eggs and cook until scrambled. Remove the eggs to a plate then add the sesame oil and olive oil to the pan and let it heat for 1 minute. Add the diced onion and garlic to the pan and cook, stirring, until the onion is translucent, about 3 minutes.
Add the cauliflower rice, peas, carrots, soy sauce, 1/2 teaspoon salt and 1/4 teaspoon pepper to the pan and cook, stirring, until the cauliflower is softened slightly, about 5 minutes. Return the scrambled eggs to the pan then add the diced pineapple and cook, stirring, for 2 minutes.
Garnish the cauliflower fried rice with scallions and serve.