Drain tomatoes well in a colander. Be sure to remove all the liquid.

Dice tomatoes.

Place diced tomatoes in a medium bowl. Add diced jalapeno and diced red onion. Mix well.

Squeeze lime juice over salsa. Mix well.

Taste. Add salt, to taste.

This can be done in advance - Store in a tightly sealed container, in the refrigerator, until ready to use. Allow to come up to room temperature before using.

Place butter and flour in a medium pot.

Place over medium heat. Cook, stirring constantly with a whisk, until the butter melts and forms a roux (thick paste) with the flour. Continue to cook over heat for a few minutes until the roux turns a light tan color.

Slowly pour milk, 1/3 cup at a time, into the roux, whisking continuously so no lumps form, until all milk is incorporated. (At this point you have a basic bechamel sauce.)

Continue to simmer this until it thickens, stirring frequently. Do not burn.

Add grated cheese -- yes, stirring constantly. ;)

Once cheese is melted, taste. Add salt and pepper, to taste. (If queso dip is too thick, add a bit more milk to thin it.)

This can be done in advance - Store in a tightly sealed container, in the refrigerator, until ready to serve. Reheat, in the microwave or on the stovetop, to very warm or even hot before serving.

Pour all prepared and warmed queso dip into a large serving bowl.

Add prepared room-temperature salsa directly into the center.

Serve like this or stir the queso and salsa together before serving.

Serve with tortilla chips or other dippers.

Dip should stay good to eat as it cools. But if you like, reheat in the microwave.