Drain water from tofu and place on a rimmed plate and top with a weight plate to press for at least 15 minutes prior to cooking. Cut pressed tofu into 1 inch cubes.
Chop the bell peppers and carrot. Mince the garlic and thinly slice the onions.
Add amaranth and water or vegetable broth to a saucepan, bring to a boil. Reduce heat, cover, and let simmer for 25 minutes. Allow to simmer until liquid is absorbed.
Meanwhile, heat a large sauté pan over high heat. Add pressed tofu and cook until it begins browning.
Reduce heat to medium and add olive oil. Add garlic, bell peppers, carrots, and spinach. Cook until vegetables are tender.
Add cooked amaranth to the sauté pan and continue cooking.
Add cumin, paprika, and crushed red pepper flakes. Salt and pepper to taste.