Rikku's not exactly trained in hand-to-hand, but all of her fighting experience is at close range/melee level. Rikku's weapon is essentially a spiked glove, so most of her weapons experience carries over here; in the few fights in-game where she doesn't have it, she fights the same, but with punches instead of slashes.

She's not trained in any particular martial arts fighting techniques; she's more the street fighter type who learned to fight by being in fights.

While in Fandom, she's been doing a lot of no-weapons hand-to-hand sparring with Deadpool and Reno.