Valinejad beat Serbia’s Nadica Bozanic of Serbia in the women’s under 63 kilogram final 23-17.
She had already defeated Natali Iyad Adnan Hamaidi from Jordan 12-2 and then beat Mexican athlete Leslie Xcaret Soltero García 26-22.
Eshkavarian also defeated Badr Achab of Belgium in men's under-73kg division gold medal match 17-16.
He had previously defeated Qiu Hong-Sheng from Chinese Taipei 19-17 and Ecuador’s Darlyn Padilla 29-5.
The taekwondo tournament at the 2018 Summer Youth Olympics has brought 100 athletes at Parque Polideportivo Roca in Buenos Aires.