First get on with the beans: put the 1/4 cup of olive oil in a saucepan add in the garlic and the lemon zest and warm through.
Drain the beans and rinse under tap water, then add to the pan and warm through, stirring and squishing with a wide, flat spoon so that the beans go into a nubbly mush. Season, to taste. Some beans are saltier than others.
Meanwhile, heat a teaspoon of oil in a large frying pan or skillet and cook the steaks on high for about 1 1/2 minutes a side and remove to warmed plates, sprinkling some salt, to taste, over them as you do so.
Squeeze the lemon juice into the hot pan and let it bubble up with the meaty oil, then pour over the steaks. Serve immediately with the mash.