Slice the onion and bell pepper, then lay them into the bottom of a 4-quart or larger slow cooker. Place the chicken pieces on top of the onion and bell peppers. Sprinkle the cumin, salt, garlic powder, and some freshly cracked pepper onto the chicken pieces. Pour the salsa over top.
Cover the slow cooker and cook on high for four hours or low for 8 hours.
After cooking, carefully remove the chicken pieces with tongs. Use the tongs to retrieve the onion an d bell peppers from the liquid in the slow cooker. Serve the chicken with the onion and bell pepper, and a spoonful or two of the juices from the slow cooker.
To build the bowls, thinly slice the jalapeño and crumble the queso fresco. Drain and rinse the black beans. Place a cup of cooked rice in a bowl, add one or two pieces of chicken, 1/4 of the beans, a few slices of jalapeño, a little crumbled queso fresco (about 1/2 oz.), and some fresh cilantro leaves. Cut a lime into wedges and squeeze the juice over top just before serving.
*You can use any type of chicken you like (drumsticks, thighs, breasts), bone-in or boneless. Just be sure to remove the skin before cooking.**Monterey jack or cheddar would also be great with these flavors if you can't find queso fresco.