Heat oil in a large saute pan over medium high heat.
Add ground turkey, onion, red and green bell peppers. Cook for 4-6 minutes or until ground turkey is browned.
Add taco seasoning, mix well to combine.
Add entire can of tomatoes including the juice. Reduce heat to medium low and simmer for 5 minutes.
Add black beans and pinto beans. Mix well and continue cooking for an additional 5 minutes or until beans are warmed thru. Taste and season with additional teaspoon of salt if desired.
Add spinach, stir to combine. Cook for an additional 1-2 minutes or until spinach has wilted.
Remove from heat, sprinkle with cilantro and squeeze of fresh lime juice if desired.
To build the tacos spoon the meat mixture into lettuce cups and immediately top with cheese so the heat of the meat will melt the cheese.
Serve with your choice of additional toppings (see serving suggestions)