Preheat the oven to 325 F. Lightly grease 9-by-13-inch casserole dish.
In a skillet over medium high heat, cook ground beef. Strain the fat. Set the cooked meat aside.
To make sauce: In a dry saute pan over medium heat, toast spices for 1-2 minutes or until fragrant. Add chicken stock and sour cream and bring to boil. In a small bowl, dissolve cornstarch in soy milk then add it to the chicken stock mixture and slowly return to a boil. Remove from heat.
To make filling: In a skillet, heat oil and saute garlic for 1 minute. Add onion and saute until lightly brown. Add zucchini and peppers and cook 2 minutes longer while stirring. Remove from heat. Allow mixture to cool 5 minutes. Add tomatoes, beans, ground beef and 2 tablespoons of sauce. Mix well.
To assemble: On a cutting board or countertop, lay tortillas flat. Lightly brush each with a small amount of sauce. Place about 1/4 cup of filling mixture in each tortilla and roll up lightly. Place rolled tortillas in casserole dish, seam-side down. Top with remaining sauce. Grate cheese over the top.
Bake 20-25 minutes or until internal temperature is 165 F. Sprinkle the cayenne pepper on top if you choose. Serve immediately.