Black Bean and Cous Cous salad

1 onion (finely chopped)
1 green bell pepper (cut into 1 cubic cm pieces)
2 Roma tomatoes (1 cubic cm pieces again)
1/2 cup sliced mushroom
1 celery heart (finely cut)
1 15 oz can black beans
2 cups plain couscous
1/4th tbsp olive oil
2 cups water
salt to taste
cilantro leaves for garnish

Heat olive oil in a pan add onion and mushrooms and cook till onions turn transparent. Add cous cous to pan and 2 cups of water. Add salt to taste. Cook couscous till it is fully done and fluff out with a fork. Cool and mix in with other ingredients. Garnish with cilantro leaves and serve. You can also cook the couscous in broth for flavor or add olives.