Both Tondela and Rio Ave are usually low-scoring, I think it would be the same today and so I will do a bet on under 2.5 goals @ 1.791.
Yes, under 2.5 goals is the first choice for that match. Tondela is one of the most defensive teams in Europe. I think Rio Ave will win this match 1-0 or 2-0. I don't expect both teams to score. Maybe first half draw would be another good choice.