ETRTO 349 is the Brompton wheel size. Brompton uses 35mm wide tires. So, 35x349 is the usual tire size in ETRTO 349.

There are almost no narrow tires in ETRTO 349, the only narrow tire is the Joseph Kuosac Strozzapreti 25x349.

If 28mm fits, there is the Velotto Fantome mini 28x349 in black or cream.

Note that these two tires aren't really fast.

The fastest tire in ETRTO 349 (and also ETRTO 406) is the Scorcher 120. This high pressure wide tire was designed to maximize speed.