Toss the red onion, cilantro, black beans, wild rice, dried cranberries, and cashews together in a large mixing bowl.
Whisk the orange juice, olive oil, tarragon vinegar, Dijon mustard, thyme, cumin, cayenne pepper, salt, and black pepper together in a small bowl; pour over the rice mixture in the mixing bowl and toss to coat. Chill 30 minutes.
