Zucchini, Avocado, and Jalapeño Tartine

2 small zucchini (10 ounces total), peeled lengthwise into very thin ribbons

Kosher salt

2 avocados, halved, pitted, peeled, and thinly sliced crosswise

1 jalapeño (ribs and seeds removed for less heat, if desired), thinly sliced

1/3 cup coarsely chopped fresh cilantro

1 lime, halved

1 loaf ciabatta, split and toasted

Extra-virgin olive oil, for drizzling

Flaky sea salt, such as Jacobsen, and freshly ground pepper