Place a dry medium pot over medium high heat. Add the couscous and cook, stirring occasionally, until it turns a bit deeper golden, about 3 minutes. Turn the couscous into a large bowl. Add 1 ¾ cups water, 2 tablespoons olive oil, ½ teaspoon kosher salt to the pot and bring to a boil. Once boiling, add the toasted couscous (save the bowl for mixing the salad), stir, then cover the pot and remove from the heat. Let stand for 10 minutes, then uncover the pot. The couscous should have absorbed all of the liquid and become tender; fluff with a fork (or if need a few more minutes, just recover the pot).
Spread the couscous out on a rimmed baking sheet to cool. Drizzle with 1 more tablespoon of olive oil and stir then spread out again.
While the couscous is cooling, heat a large skillet over medium high heat. Add 1 tablespoon of olive oil, then add the celery and saute for 2 minutes. Add the radicchio and ramps or scallions and saute for another 2 minutes until the vegetables are starting to become tender. Stir in the jalapeno and cook for one more minute, then remove from the heat and stir in the lemon zest.
Turn the cooled couscous into the reserved bowl, and add the vegetable mixture. Stir to combine, seasoning with salt and pepper. Transfer to a serving bowl (or not) and drizzle with just a bit more olive oil for good measure.
Note: Ramps are wild scallions or leeks, available during the spring in certain parts of the country (and other parts of the world). They are like garlicky scallions, so if you use them instead of scallions, know that your couscous scallion will be more full onion-family flavored. If you prefer, use ½ cup of chopped ramps if you find the flavor a little overpowering.