The sesame wok oil is gonna add a really lovely nuttiness to the roast potatoes, but also because this oil has a really high burning temperature, it's gonna make them really crispy and delicious.
Now for the savory part, soy sauce will be our base here, but we're intensifying it with a pinch of both salt and msg, a few drops of sesame oil for nuttiness and of course spinach his best friend garlic.
Personally, I think if you just use extra-virgin it's quite strong and it can overpower some of the fragrance and the nuttiness of the pesto, but it's up to you.