Preheat the oven to 400 F.
Trim the chicken breasts and place in a large bowl. Drizzle with olive oil and turn to coat. Sprinkle with chipotle and salt and massage to distribute the spices evenly. Sprinkle with lime zest. Place the breasts on the sheet pan and roast for 20-25 minutes, until a thermometer inserted in the fat part of a breast reads 165 F. Cool on a rack until cool enough to handle, then shred the chicken into strips. Keep warm, or cover and refrigerate until time to serve.
For the fonio, place the water, beets and salt in a 2 quart saucepan and bring to a boil. Cover and reduce the heat to low, and cook for 15 minutes. When the beets are tender, add the olive oil, then gradually pour in the fonio, stirring constantly so there are no lumps. Cover the pan and take off the heat, let stand for five minutes. Fluff the fonio with a fork.
While the beets cook, place the lime juice, sour cream, avocado and salt in a blender, in order. Blend on lower speed until pureed, raising the speed to make a smooth sauce. Scrape down and repeat as needed to make a creamy puree.
To serve, spread 3/4 cup fonio on a plate, then top with 1/4 of the chicken and about 1/4 cup crema. Garnish with cilantro and serve.