Can you tell me if there are exercises that will help improve circulation to my leg ulcer?

Depends on the ulcer: It is important to know the type of ulcer that you have and if there is any swelling. This is a complex issue and should be evaluated by a vascular surgeon to identify the primary cause of the ulcer and any mitigating factors that may be making the ulcer worse. There is no specific exercise for this problem and again this should be evaluated by a vascular surgeon with a special interest in this.

Walk: If ok with your doctor walk. Also no smoking.

Ulcer: Firstly the need to define what type of ulceration you have. Venous ulcerations are secondary to venous reflux, and should be managed by destroying the problem of the reflux, usually accomplished by thermal ablation of the vein. Arterial ulcers are secondary to arterial insufficiency, and should be treated by identifying the arterial problem treating it. Exercise with walking Is important