Make the vinaigrette. In a small container, combine the shallots, lemon juice, rice vinegar, olive oil, salt and pepper. Shake to blend.
Place the arugula in a large serving bowl with the onion. Peel the oranges, and use a paring knife to remove all of the white pith from the outside of the fruit. Cut the oranges crosswise into slices, and cut those slices into 4 pieces. Add these to the bowl. Pour the dressing on the salad, and toss to combine. Scatter the pomegranate seeds over the top and serve.
Notes
You can buy pre-shelled pomegranate seeds in little containers in the produce section of the supermarket, or if you’re feeling industrious, buy a whole pomegranate and remove the seeds yourself. It’s messy but slightly therapeutic work. If you have kids, lay out lots of paper on the table, put them in big t-shirts that can get messy, and let them take on this project. If you live in a place where it’s warm enough to do this outside — definitely go outside.You can also do this in a bowl of cold water, preferably placed in the sink, which helps the pomegranate seeds release from the white pithy membrane that ensconces them.