Not free going by previous threads. If you do a search (blue button towards top right that says "search this forum") you will find a number of threads including this one. Looking at the nutritional info on the thread they seem to be quite high in fat and so also syns.
Wasabi paste has about 15 calories per Tbsp. I wouldnt use as much as that with sushi/bento, so 1 syn max? That's is you're using the whole tablespoon.