Cook barley according to package instructions. When cooked, remove from heat and drain. Allow barley to cool completely.
To make the cauliflower rice, chop each cauliflower into small florets. Transfer florets to a large food processor and process until rice-sized pieces are formed (you may need to do this in batches).
Heat a large skillet over medium heat. Add 1-2 teaspoons olive oil and the riced cauliflower to the skillet. Cook over medium heat for approximately 3-4 minutes, stirring frequently (the goal is not to fully cook the cauliflower- more like warm through). Remove cauliflower from the skillet and transfer to a large serving bowl.
To the cauliflower add the cooked barley, red onion, chopped almonds, parsley, mint, chopped oranges and orange zest, pomegranate arils, sunflower seeds, and watermelon radish. Toss to combine.
Prepare the vinaigrette. In a jar with a tight-fitting lid, add the orange juice, lemon juice, olive oil, red wine vinegar, and salt and pepper, to taste. Shake well to combine.
Drizzle salad with desired amount of vinaigrette and mix well to combine.