Place a medium saucepan over medium-high heat with 2 turns of the pan of EVOO, about 2 tablespoons. Add the andouille to the pan and cook until golden brown, 5-6 minutes. Remove the sausage from the pan and reserve on a plate.
Add the orzo to the pan the sausage was cooked in and toast until golden brown, 2-3 minutes. Add the onion, garlic, celery, pepper and bay leaf to the pan, and cook until the veggies are tender, about 5 minutes. Season everything with salt and pepper and add the hot sauce, Worcestershire, thyme sprigs, beans, rice and reserved sausage to the pot. Stir in the stock plus 2 cups water and bring up to a bubble. Reduce the heat to medium and simmer until the rice and pasta are cooked through, 16-18 minutes.
Just before serving, remove and discard the bay leaf and thyme sprigs and season as needed with salt and pepper. Serve garnished with scallions.