I do alot of tricep exericises. YOu can do tri-cep dips (you don't need weights) You can do tricep kickbacks to. If you don't have wieghts use milk jub with water in them or heavy cans. Anythis with weight to it is good.
This is just a side note: My cousin's wife had that bariatric surgery a lost a lot of wieght. She looks really good! She then had all excess skin cut off (I think she had her arms done too) She does not work out like she should at all and her triceps hang very badly now. Just shows how much that muscle relies on maintenance.