The sauce works just as well with salmon fillets or tofu if you want to ring the changes.
Use tamari instead of soy sauce and check your rice wine vinegar is GF (most are, but check). Everything else is naturally gluten free.
An easy hack for recipes like this is to use frozen cubes of crushed ginger and garlic — you can buy them in most supermarkets, either pre-mixed or as separate cubes. Makes cooking Asian food much more efficient.
The sauce works just as well with salmon fillets or tofu. The cucumber side is worth making — it cuts through the sweetness and takes two minutes.