Prep and Combine: Wash and pat dry the lettuce leaves. In a small bowl, whisk together cumin, ancho chili powder, smoked paprika, granulated garlic, Mexican oregano, and optional cayenne.
Sauté the Base: Heat olive oil in a large Dutch oven over medium heat. Add onion and bell pepper and cook 4 to 5 minutes until beginning to soften. Stir in tomato paste and the spice blend and cook 1 minute until fragrant.
Brown the Turkey: Add ground turkey. Cook, breaking into fine crumbles, 6 to 8 minutes until no longer pink.
Simmer the Sauce: Stir in no-salt-added chicken broth, scraping up browned bits. Bring to a simmer.
Reduce and Thicken: Lower heat to maintain a gentle simmer. Cook uncovered 20 to 25 minutes, stirring occasionally, until the mixture is thick enough to coat the turkey with no pooling liquid. Verify food safety with an instant read thermometer. The turkey mixture should reach 165°F (74°C).
Assemble and Serve: Spoon the warm turkey filling into lettuce leaves. Garnish with cilantro and serve with lime wedges for squeezing.