There are several different shades of meaning depending on the precise useage. "Estoy cocinando la cena" is literally "I am cooking dinner". It means that at the present time, I am engaged in the act of cooking. If you mean "I am cooking dinner tonight when you come over", it would be more like "Voy a cocinar la cena", or "yo cocino la cena esta noche". For "I am cooking dinner at the Christmas party this year", you could say "Cocinaré la cena a la fiesta de la Navidad este año".
The Spanish translation for "Help with dinner" would be either:
Ayudar hacer la cena (help make the dinner) or
Ayudar con la cena (Help with dinner)
"Help me with dinner" would be:
Ayúdame hacer la cena or
Ayúdame con la cena.
Cena de camarones.
Tiene usted camarones?
(Una) hamburguesa para cenar
camaron
dinner specials
cenar
camaron frito
Tengo cena
Cena
Cóctel de camarón.
Una cena sabatina
Cena para diez
¿Vamos a cenar?
¿Cuantos para cenar?
Puedo comer cena contigo?