For the dressing, combine rice vinegar, olive oil, onion, mint and cumin. Taste and adjust mint and cumin. Set aside.
Line a serving platter or individual salad plates with radicchio or lettuce leaves. Arrange orange slices over lettuce. Sprinkle with dates and pistachios. Drizzle with dressing.
Notes
* Rice vinegar is mildly tangy compared to most vinegars -- just 4% acidity. And seasoned rice vinegar has a bit of salt and sugar added, making it an ideal match for all kinds of fruits, citrus included.