Whenever the device turned ON, BLE will be started(if CyBle_Start() function is called) and CYBLE_EVT_STACK_ON event will be generated, if you call CyBle_GappStartAdvertisement() function in that event then device starts advertising (Cysmart App can scan and connect to that device). Please refer to the 'BLE_FindMe' code example in the PSoC Creator.
If you are doing the Pairing process (i.e., two devices are authenticated, encrypted and exchanges secured data over the BLE interface) then bonding can be used, in which the keys and the identity information exchanged during the pairing process are saved. After devices are bonded, they do not have to go through the pairing process again when reconnected.
Please refer to the Day015_Bonding example project from the GitHub for more information on bonding.