Make a red curry paste by combining the tomato paste, garlic, ginger, chili powder, cumin, coriander, soy sauce, 1 tablespoon lime juice, and turmeric in a medium pot.
Cook on low heat, stirring occasionally for 5 minutes.
Add the pumpkin puree and simmer for 5 minutes.
Add the oil to a large pot over medium-high heat.
Saute the onion and bell pepper for 8 minutes.
Add the cubed tofu and cook for 15 minutes, stirring frequently until the edges start to brown.
Add the pumpkin and red curry paste mixture, coconut milk, broth, sugar, salt, and pepper. Bring to a boil, then cook on low for 10 minutes.
Stir in spinach and remaining lime juice and cook for 3 minutes or until the spinach has wilted.
Top the tofu pumpkin curry with cilantro if desired and optionally serve with rice.