Prepare couscous according to package directions. Transfer to a colander and rinse under cold water.
In a blender, puree the basil, EVOO and vinegar until smooth. In a large bowl, toss the couscous with the basil vinaigrette. Toss in the corn, red onion, chile and feta; season with salt and pepper.
Serve couscous salad on a bed of baby spinach.