In large saucepan, heat oil over medium-high heat. Add onion, peppers, jalapeños and garlic; sauté until softened, about 5 minutes.
Add tomatoes, water, brown sugar, cumin, cinnamon, and salt, stirring to dissolve sugar. Add sweet potatoes and beans. Cover; bring to boiling. Reduce heat; simmer, covered, stirring occasionally, until potatoes are tender, 40 minutes.
About 5 minutes before stew is finished cooking, prepare couscous according to package directions.
To serve, spoon stew over couscous. Sprinkle with cilantro. Makes 8 servings.