In a large skillet over medium-high heat, cook sausage, breaking it up with a wooden spoon, until browned and cooked through, about 5-10 minutes.
Drain excess grease if needed, leaving a small amount for flavor. Add diced onion and bell pepper. Cook, stirring often, until softened, about 5 minutes.
Add rice, white beans, diced tomatoes with juice, Italian herbs, garlic powder, salt, red pepper flakes, and water. Stir to combine.
Reduce heat to medium, cover with lid, and simmer for about 40 minutes, stirring occasionally, until rice is nearly tender and most water has been absorbed.
Add spinach a few handfuls at a time, stirring until wilted.
Cover and cook 2-5 more minutes until rice is fully cooked and water has evaporated. Remove from heat and serve.
