Bring the water to a boil in a saucepan. Remove from the heat and stir in the couscous. Cover and let stand until the couscous absorbs the water entirely, about 10 minutes; fluff with a fork.
While the couscous soaks, stir the feta cheese, jalapeno pepper, cucumber, garlic, green onion, mint, basil, cilantro, parsley, cumin, cayenne pepper, and lemon juice in a large bowl. Add the prepared couscous and mix well.