To a 4-qt slow cooker, arrange orange slices on the bottom. Arrange salmon fillets, skinned side down over top oranges. Drizzle oil evenly over fillets. Sprinkle evenly with cumin, pepper and salt. Cover and cook on low for 2 1/2 to 3 hours, until opaque in center, checking for doneness after 2 1/2 hours (or on high for 1 1/4 to 1 1/2 hours, checking for doneness after 1 1/4 hours).
Combine salsa ingredients about 15 minutes before serving; set aside until needed.
To serving plates, gently transfer fillets, discarding orange slices and any accumulated liquid. Top with salsa.
Serving Size: 1 orange salmon fillet and 1/4 of salsa