In Tanzania, some people serve this salad for breakfast. Cucumber and avocados can be served alongside smoked fish or shellfish, but people from the coast of Tanzania would add a salted fish, such as salted cod.
This recipe is also in Taste of Tanzania: Modern Swahili Recipes for the West, cookbook
In a big bowl, mix all ingredients except avocado. Cover and set aside to chill for 30 minutes. Peel and cube avocadoes and add them to the other ingredients only when you are about to serve, so that they will not turn brown.