Chicken Stew with Okra

Arrange chicken in 1 layer on a tray, then sprinkle with salt and let stand at room temperature 30 minutes.
While chicken stands, pulse tomatoes with their juice in a food processor until finely chopped.
Stir water into tomato paste in a small bowl until smooth.
Pat chicken dry. Heat oil in a 10- to 12-inch heavy skillet over moderately high heat until hot but not smoking, then brown chicken, without crowding, in 3 or 4 batches, turning over occasionally, until golden, about 6 minutes per batch. Transfer with tongs as browned to a 6- to 7-quart heavy pot. Pour off all but 2 tablespoons fat from skillet, then add onion and cook over moderate heat, stirring occasionally, until edges are golden, 2 to 3 minutes.
Add onion, chopped tomatoes, tomato paste mixture, garlic paste, and cayenne to chicken in pot.
Whisk together peanut butter and 1 cup broth in a bowl until smooth, then add to chicken along with remaining 3/4 cup broth, stirring to combine well (chicken will not be completely covered with liquid). Bring to a boil, uncovered, then reduce heat and simmer, covered, stirring occasionally (to prevent sticking), until chicken is very tender, 25 to 30 minutes.
Peel sweet potato and cut into 1-inch chunks. Stir into stew along with okra, then simmer, covered, until potato is tender but not falling apart, 10 to 12 minutes.