Marinate the chicken: Make the chicken marinade by combining the chopped mango, extra-virgin olive oil, lemon juice, pressed garlic, dried oregano, ground cinnamon, kosher salt and ground pepper in a high speed blender. Blend until smooth and combined. Optional: Reserve ¼ cup of the marinade and put aside to use as a sauce for the tacos.
Add the chicken breasts to a medium bowl and then pour the marinade over top of the chicken. Toss the chicken to coat in the marinade and let sit on the counter for 20-30 minutes.
Make the mango pico de gallo: In a medium bowl toss together crumbled feta cheese, fresh minced cilantro, diced mango, diced tomatoes, extra-virgin olive oil, kosher salt and lemon juice. Set aside in the fridge.
Make the beans: Add olive oil to a medium sized pot and heat over medium heat. When warm, add the onion and cook for a few minutes until softened. Add the garlic, salt and pepper and cook for 1 minute. Add the white beans with ¼ cup water and cook until the water is mostly gone and beans are softened. Remove from heat to a bowl, smash the beans with a fork and stir in the monterey jack cheese until you get a paste-like texture.
Cook the chicken: If it's nice out, grill the chicken: Once marinated, remove the chicken breasts from the marinade and place on a plate. Heat the grill to medium-high heat, about 400-425F. Once heated, oil the grill well and place the chicken breasts on the grill. Cook, turning every 5-6 minutes, for about 12-15 minutes or until cooked through (or until an instant-read thermometer inserted into the thickest part registers 165F). Remove the chicken from the grill and let rest while you make the smashed bean tacos.If it's not grilling season, cook in a skillet: After the chicken has marinated for 20-30 minutes. Heat a large non-stick skillet over medium heat. When the skillet is hot, place the chicken breasts in the skillet. Cook, turning every 2-3 minutes, for about 12-15 minutes or until cooked through (or an instant-read thermometer inserted into the thickest part registers 165F). Remove the chicken from the skillet and let rest while you make the smashed bean tacos.
Assemble the tacos: Press 2-3 tbsp of the bean mixture onto a tortilla, making sure it’s as thin as possible so it cooks quickly. Heat a non-stick skillet over medium heat and add 1 tbsp avocado oil or olive oil or use cooking spray. Once the skillet is hot, place the tortilla bean side down. Flatten/smash it into the pan using a flat surface (i.e. bottom of a small pot or frying pan or a metal flipper). Cook until browned and crispy, about 3-4 minutes and then flip the tortilla and cook another 1-2 minutes. Remove from the pan and repeat with the remaining tortillas. **Add more oil or cooking spray to the pan if the bean mixture starts to stick to the pan**
To serve: Chop up the chicken breasts into small bite sized pieces (or slice if preferred) and add to the tacos along with the mango pico de gallo. Optional: Drizzle the reserved marinade over the taco (if you kept some aside) or use your favorite hot sauce.