Welcome, Evary! I hope you'll stop in the Welcome Forum to write a brief introduction of yourself.
I don't know your location (specifics certainly aren't necessary), but I'll take a wild guess you're in the USA somewhere. I'm no kitchen designer or architect, but I'd think the look of oval windows would have to work with the general theme of your house.
I love a kitchen with windows, but keep in mind that if you're putting them next to a stove and/or cook top, they'll get some extra grease and condensation on their inside surfaces, requiring more frequent cleaning. In that case, I'd recommend getting any trim or mullions (the strips that divide panes- or seem to) within the double panes. It would make cleaning vastly less complicated.
I've not seen an oval widow that opens from the top or bottom, but if you need ventilation from the windows, they'd probably need to be hinged, right? Keep clearances in mind, as you would with a doorway.
The size of your stove may dictate the distance between the windows. I'm sure that condition would also guide the size of the windows.
Good luck! Let us know how things turn out.
(P.S.- I advise you to remove the commercial link in your signature. Check the community guidelines for the site.)