The “trick” I use to get the identity key out of the browser is to open the javascript console and enter the following:
var ix = 0
var reduxState = JSON.parse(localStorage.redux)
var state = reduxState.committedState[reduxState.currentStateIndex]
// get the 0th identity address
state.state.account.identityAccount.keypairs[ix].address
// get the 0th identity key
state.state.account.identityAccount.keypairs[ix].key + '01'
That gives you the ownerKey of the 0th-index account in the browser. To get a different index, use a different value for ix.
To get a payment key, I always just generate a new one for a subdomain registrar. There’s many different ways to generate a private key and bitcoin address, but I usually just use node and bitcoinjs-lib. So, from a directory with bitcoinjs installed (just create a new directory and run npm install bitcoinjs-lib), run node and then these commands will make a bitcoin address and private key string:
var btc = require('bitcoinjs-lib')
var paymentPair = btc.ECPair.makeRandom()
var paymentAddress = paymentPair.getAddress()
var paymentKey = paymentPair.d.toHex() + '01'
To fund that paymentKey, you can just send bitcoin to the paymentAddress.