In a small pot, combine rice, ¾ cup water (1½ cups for 4 servings), and a pinch of salt. Bring to a boil, then cover and reduce to a low simmer. Cook for 10 minutes.

Drain beans.

Once rice has cooked 10 minutes, stir in drained beans; cover and cook until rice is tender, 5-8 minutes more.

While rice and beans cook, wash and dry produce.

Trim and thinly slice scallions, separating whites from greens. Peel and mince or grate garlic. Trim and discard root end from lettuce; thinly slice half the lettuce (all for 4 servings) crosswise into ribbons. Dice tomato into ¼-inch pieces; season with salt and pepper.

Heat a drizzle of oil in a large pan over medium-high heat. Add beef*, scallion whites, garlic, cumin, salt, and pepper.

Cook, breaking up meat into pieces, until cooked through, 4-6 minutes. Taste and season with salt and pepper if desired.

Keep covered off heat until ready to serve.

In a small bowl, combine sour cream and scallion greens. Add water 1 tsp at a time until mixture reaches a drizzling consistency. Season with salt and pepper.

Fluff rice and beans with a fork; taste and season with salt and pepper.

Divide rice and beans and beef mixture between shallow bowls in separate sections. Top everything with sliced lettuce, tomato, and scallion crema. Serve.