Place a dry 10-inch skillet over medium-high heat. Add the orzo and toast until golden brown and nutty-smelling, about 10 minutes, tossing the pan frequently. Remove from the heat and cool.
In a large serving bowl, whisk together the lemon juice, zest, olive oil, cumin, salt, and a good 10 grinds of pepper.
Bring 3 quarts salted water to a boil and cook the orzo until al dente. Add the asparagus during the last 2 or 3 minutes of cooking. Drain in a colander, then immediately run under cold running water for about 30 seconds. Drain well and transfer to the serving bowl.
Add the chickpeas, dill, feta, green onions, cucumber, arugula and pine nuts to the bowl and gently toss together. Taste for seasoning, adding more salt, lemon or olive oil if needed. Serve at room temperature.
The pasta salad keeps well for a day or two. Serve at room temperature for the best flavor.
To toast pine nuts, heat them in a small skillet for about 5 minutes over medium heat until they turn lightly golden. Keep an eye on them, because they can go from toasted to burned very quickly.