Tri-Tip is great. Just trim the outer fat and you're good.
Flank is real nice. Marinate it overnight with the following.
1/2 low sodium soy sauce.
1/2 cup worchestchire sauce
juice of 1 lemon,lime and orange.
smash a couple cloves of garlic
salt and pepper and some Tabasco Chipotle.
Get the grill real hot and throw the steak on for 7 minutes, flip, cook for another seven minutes and you're done. Don't touch the steak when its on the grill, no peaking, prodding, nothing. Just let it cook. Once done let it rest for about 10 minutes on a plate. Then slice it against the grain and enjoy. This is the best. I like to grill some onions and peppers and roll it in a tortilla.