code: public void removeUser(String email, String password, final SimpleLoginCompletionHandler handler) {
      final SimpleLoginAuthenticatedHandler authHandler = new SimpleLoginAuthenticatedHandler() {
        public void authenticated(FirebaseSimpleLoginError error, FirebaseSimpleLoginUser user) {
          handler.completed(error, false);
        }
      };
  
      if (!Validation.isValidEmail(email)) {
        handleInvalidEmail(authHandler);
      }
      else if (!Validation.isValidPassword(password)) {
        handleInvalidPassword(authHandler);
      }
      else {
        HashMap<String, String> data = new HashMap<String, String>();
        data.put("email", email);
        data.put("password", password);
  
        makeRequest(Constants.FIREBASE_AUTH_REMOVEUSER_PATH, data, new RequestHandler() {
          public void handle(FirebaseSimpleLoginError error, JSONObject data) {
            if(error != null) {
              handler.completed(error, false);
            }
            else {
              try {
                JSONObject errorDetails = data.has("error") ? data.getJSONObject("error") : null;
                if(errorDetails != null) {
                  handler.completed(FirebaseSimpleLoginError.errorFromResponse(errorDetails), false);
                }
                else {
                  handler.completed(null, true);
                }
              }
              catch (JSONException e) {
                e.printStackTrace();
                FirebaseSimpleLoginError theError = FirebaseSimpleLoginError.errorFromResponse(null);
                handler.completed(theError, false);
              }
            }
          }
        });
      }
    }
docs: Remove a Firebase "email/password" user.
  
  @param email Email address for user.
  @param password Password for user.
  @param handler Handler for asynchronous events.