Heat oil in a large saucepan over medium-high heat. Add the ground beef, onions, peppers, garlic, cumin, black pepper, salt and sauté until just turning golden.
Add the tomato paste, chipotle in adobo and cook for 2 minutes. Add the chicken stock and simmer until reduced by two-thirds, mix the refried beans and adjust seasoning.
Cut Crackets® in half with serrated knife, add stewed beef and beans into the Crackets® , and serve as little tacos. Top with julienne iceberg lettuce, diced tomato, sour cream and cheddar cheese if desired.