Make the couscous: In a small saucepan, bring 1 cup of water to a boil. In a medium bowl stir together the dry couscous, turmeric, and salt. Pour the boiling water over the couscous, cover and let sit for about 5 minutes, until the water is absorbed and the couscous is tender. Fluff with a fork and set aside or put in the fridge to cool.
Make the dressing: In a small bowl, whisk together the lemon juice, olive oil, honey, oregano, garlic, salt, and pepper.
In a large bowl, combine the chopped tomatoes, bell peppers, cucumbers, parsley, green onions, and chickpeas. Add the dressing and stir to combine.
Divide the couscous between four bowls, add the vegetables, and top with tzatziki and hummus. Garnish with sliced radishes and chopped parsley.