Heat the oil in a medium pot over medium-high heat. Add 1/2 cup pico de gallo, the chopped chipotle and adobo sauce to taste; cook until the mixture starts to sizzle, about 2 minutes. Add the beans and 3/4 cup water; bring to a low boil, then stir in the chicken and cook until the mixture is slightly thickened, about 2 minutes. Stir in the cilantro and season with salt.
Heat the tortillas as the label directs. Arrange the rice horizontally in the lower half of each tortilla, leaving a 1 1/2-inch border on all sides. Top evenly with the cheese, chicken mixture, lettuce and the remaining pico de gallo.
Fold the bottom edge of each tortilla snugly over the filling, tuck in the sides and roll up tightly. Cut the burritos in half and serve with guacamole if using.