Add oil, tomato purée and chicken. Simmer until sauce thickens slightly and clings to meat, 10-15 minutes. Season with salt. To serve, divide tinga among 4 plates along with rice and beans.

Add the red beans, chicken stock and sausage. Simmer covered for about 10 minutes. Uncover and simmer for an additional 15 minutes. Serve on top of the rice, and garnish with the chopped chives.