I made turkey meatballs last night with a spicy tomato sauce. The kids had them with pasta and I had them with roasted veg.
I think to make a syn free burger you need to chop a shallot very finely, break up the mince, add the shallot and either some chilli powder or chilli flakes, I'd put some salt and pepper in there and a splash of worcester sauce. You do need quite a bit of seasoning as I find turkey mince a bit bland. Add a small beaten egg and shape into patties.
I baked my meatballs in the oven at gas mark 7 for about 15 minutes on a baking sheet sprayed with fry light. For burgers you probably want to at an extra 5 minutes to that (depending on the size of them), or you could grill them. I wouldn't fry them as they might break up.